System and method for vehicle control in tailgating situations

ABSTRACT

A computer-implemented method for controlling a host vehicle relative to a first vehicle positioned immediately ahead of the host vehicle, including, detecting a second vehicle driving behind the host vehicle and in the same lane as the host vehicle. The method including detecting a braking operation initiated by the vehicle system of the host vehicle. The braking operation causes the host vehicle to decelerate based on an acceleration control rate in order to maintain a preceding headway reference distance with the first vehicle. The method includes, determining a relative rear headway distance between the host vehicle and the second vehicle with respect to a rear headway reference distance and modifying the acceleration control rate based on the relative rear headway distance and the rear headway reference distance. Further, the method includes controlling the vehicle system according to the modified acceleration control rate.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Ser.No. 62/442,333 filed on Jan. 4, 2017, which is expressly incorporatedherein by reference. This application also claims priority to U.S.Provisional Application Ser. No. 62/442,190 filed on Jan. 4, 2017, whichis also expressly incorporated herein by reference.

Further, this application is a continuation-in-part of U.S. applicationSer. No. 15/630,864 filed on Jun. 22, 2017, which also claims priorityto U.S. Provisional Application Ser. Nos. 62/442,333 and 62/442,190, allof which are expressly incorporated herein by reference. U.S.application Ser. No. 15/630,864 is also a continuation-in-part of U.S.application Ser. No. 15/191,358 filed on Jun. 23, 2016, which isexpressly incorporated herein by reference.

This application is also a continuation-in-part of U.S. application Ser.No. 15/630,866 filed on Jun. 22, 2017, which also claims priority toU.S. Provisional Application Ser. Nos. 62/442,333 and 62/442,190, all ofwhich are also expressly incorporated herein by reference. U.S.application Ser. No. 15/630,866 is also a continuation-in-part of U.S.application Ser. No. 15/191,358 filed on Jun. 23, 2016, which isexpressly incorporated herein by reference.

Further, this application is also a continuation-in-part of U.S.application Ser. No. 15/679,068 filed on Aug. 16, 2017, which alsoclaims priority to U.S. Provisional Application Ser. No. 62/442,333, allof which are also expressly incorporated herein by reference.Additionally, this application is a continuation-in-part of U.S.application Ser. No. 15/191,358 filed on Jun. 23, 2016, which is alsoexpressly incorporated herein by reference.

BACKGROUND

Vehicle travel can be affected by many different variables such as,other vehicles, objects, obstructions, hazards, and environmentalconditions (herein referred to as hazards). As an illustrative example,traffic congestion, lane closures, disabled vehicles, tailgatingvehicles, collisions, and/or debris on a road can cause significantdelays for vehicle travel and can compromise road safety. A driver of avehicle may be unaware of these different variables that affect vehicletravel. In some circumstances, a driver is unable to see a hazard beyonda certain surrounding of the vehicle. For example, the driver's visionmay be diminished or completely obstructed by a large vehicle, trafficcongestion, and/or weather conditions. The driver's vision is alsolimited when observing tailgating vehicles following closely behind.Further, the driver's vision may also be reduced due to road geometrysuch as curvatures.

Additionally, the driver is generally unaware of intimate knowledgeabout the dynamics of other vehicles on the road and the drivers of theother vehicles. For example, the driver may not know the speed ormaneuver intentions of other vehicles on the road. Vehicle sensorysystems (e.g., radar, camera) implemented in the vehicle can detect somehazards. However, these sensory systems have a limited detection rangewithin an immediate surrounding of a vehicle. Thus, the driver does nothave information about obstructions further ahead or behind, neither ata road level nor at a lane level, outside of the surrounding environmentof the vehicle. Vehicle communication with other vehicles andinfrastructures can address some of the hazards discussed above when theinformation communicated is synergistically applied to a vehicle or manyvehicles.

BRIEF DESCRIPTION

According to one aspect, a computer-implemented method for controlling avehicle system of a host vehicle that controls motion of the hostvehicle relative to a first vehicle positioned immediately ahead of thehost vehicle, including, detecting, using the one or more vehiclesensors, a second vehicle driving behind the host vehicle and in thesame lane as the host vehicle, and detecting, using one or more vehiclesensors, a braking operation initiated by the vehicle system of the hostvehicle. The braking operation causes the host vehicle to deceleratebased on an acceleration control rate generated by the vehicle system inorder to maintain a preceding headway reference distance with the firstvehicle. The method includes determining, using the one or more vehiclesensors, a relative rear headway distance between the host vehicle andthe second vehicle with respect to a rear headway reference distance,and modifying the acceleration control rate based on the relative rearheadway distance and the rear headway reference distance. Further, themethod includes controlling the braking operation of the vehicle systemto decelerate the host vehicle according to the modified.

According to another aspect, a vehicle system for a host vehicle thatcontrols motion of the host vehicle relative to a first vehiclepositioned immediately ahead of the host vehicle, includes a sensorsystem and a processor operatively connected for computer communicationwith the sensor system. The processor detects, using the one or morevehicle sensors, a second vehicle driving behind the host vehicle and inthe same lane as the host vehicle, and receives from the vehicle systemof the host vehicle an acceleration control rate. The accelerationcontrol rate when executed by the host vehicle initiates a brakingoperation by the vehicle system of the host vehicle to maintain apreceding headway reference distance with the first vehicle. Further,the processor modifies the acceleration control rate based on therelative rear headway distance and the rear headway reference distance,and controls the braking operation of the vehicle system to deceleratethe host vehicle according to the modified acceleration control rate.

According to a further aspect, a non-transitory computer-readablestorage medium including instructions that when executed by a processor,cause the processor to, detect a second vehicle driving behind the hostvehicle and in the same lane as the host vehicle, and receive anacceleration control rate from a vehicle system of a host vehicle. Theacceleration control rate is generated by the vehicle system to maintaina preceding headway reference distance with a first vehicle positionedimmediately ahead of the host vehicle. Further, the processor calculatesa relative rear headway distance between the host vehicle and the secondvehicle with respect to a rear headway reference distance, and modifiesthe acceleration control rate based on the relative rear headwaydistance and the rear headway reference distance. The processortransmits the modified acceleration control rate to the vehicle system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic view of an exemplary traffic scenario accordingto one embodiment;

FIG. 1B is a schematic view of vehicles in the second lane 104 b of FIG.1A according to an exemplary embodiment;

FIG. 2 is a schematic view of a vehicle communication network accordingto an exemplary embodiment;

FIG. 3 is a block diagram of a vehicle control system of a vehicleaccording to an exemplary embodiment;

FIG. 4 is a schematic view of exemplary vehicle systems that can beassociated with the vehicle of FIG. 3 according to one embodiment;

FIG. 5 is a schematic view of an exemplary interior of the vehicleaccording to an exemplary embodiment;

FIG. 6 is a schematic view of a C-ACC control model for controlling avehicle control system according to an exemplary embodiment;

FIG. 7 is a block diagram of an exemplary control system of the C-ACCcontrol system according to an exemplary embodiment;

FIG. 8 is a process flow diagram of a method for controlling a vehiclecontrol system according to an exemplary embodiment;

FIG. 9 is a process flow diagram of a method for calculating anacceleration control rate for a host vehicle according to an exemplaryembodiment;

FIG. 10 is a process flow diagram of a method for selecting a leadingvehicle according to an exemplary embodiment;

FIG. 11 is a process flow diagram of a method for monitoring acommunication link for packet loss between a host vehicle and a remotevehicle according to an exemplary embodiment;

FIG. 12 is a schematic view of an exemplary traffic scenario for hazarddetection according to one embodiment;

FIG. 13 is a process flow diagram of a method for detecting a hazard andcontrolling a vehicle control system according to an exemplaryembodiment;

FIG. 14A is a process flow diagram of a method for classifying a remotevehicle according to an exemplary embodiment;

FIG. 14B is a illustrative example used to describe classifying a remotevehicle ahead of the host vehicle of FIG. 14A according to an exemplaryembodiment;

FIG. 14C is a process flow diagram of a method for predicting lateraloffset for classifying a remote vehicle according an exemplaryembodiment;

FIG. 15 is a process flow diagram of a method for detecting traffic flowhazards based on vehicle communication and controlling a vehicle controlsystem according to an exemplary embodiment;

FIG. 16 is a process flow diagram of a method for detecting a hazardbased on remote vehicle lane change and controlling a vehicle controlsystem according to an exemplary embodiment;

FIG. 17 is a schematic view of a traffic scenario for detecting a hazardaccording to an exemplary embodiment;

FIG. 18 is a schematic view of an exemplary traffic scenario for mergeassist according to one embodiment;

FIG. 19 is a process flow diagram for providing merge assist using avehicle communication network according to an exemplary embodiment;

FIG. 20 is a process flow diagram for providing merge assist with speedguidance using a vehicle communication network according to an exemplaryembodiment;

FIG. 21 is a process flow diagram for providing merge assist withposition guidance using a vehicle communication network according to anexemplary embodiment.

FIG. 22A is an illustrative embodiment of a scenario where no radarobjects are detected, according to an exemplary embodiment;

FIG. 22B is an illustrative embodiment of a side by side merge scenario,according to an exemplary embodiment;

FIG. 22C is an illustrative embodiment of the host vehicle at tail mergescenario, according to an exemplary embodiment;

FIG. 22D is an illustrative embodiment of the host vehicle at lead mergescenario, according to an exemplary embodiment;

FIG. 22E is an illustrative embodiment of the host vehicle in betweenscenario according to a front safe distance, according to an exemplaryembodiment;

FIG. 22F is an illustrative embodiment of the host vehicle in betweenscenario according to a rear safe distance, according to an exemplaryembodiment;

FIG. 23A is a schematic view of an exemplary traffic scenario with atailgating scenario according to one embodiment;

FIG. 23B is a schematic view of vehicles in the second lane 2304 b ofFIG. 23A according to an exemplary embodiment;

FIG. 24 is a block diagram of a vehicle control system of a vehicleaccording to an exemplary embodiment;

FIG. 25 is a schematic view of a C-ACC and/or braking control model forcontrolling a vehicle control system according to an exemplaryembodiment;

FIG. 26 is a process flow diagram of a method for controlling a vehiclesystem of a host vehicle with a tailgating scenario according to anexemplary embodiment;

FIG. 27 is a process flow diagram of showing a detailed view of themethod of FIG. 26 according an exemplary embodiment;

FIG. 28 is a graph showing brake pedal force versus time according to anexemplary embodiment;

FIG. 29 is a process flow diagram of another method for controlling avehicle system of a host vehicle with a tailgating scenario according toan exemplary embodiment;

FIG. 30 is a process flow diagram showing a detailed view of the methodof FIG. 29 according an exemplary embodiment; and

FIG. 31 is a process flow showing another detailed view of the method ofFIG. 29 according an exemplary embodiment.

DETAILED DESCRIPTION

The following includes definitions of selected terms employed herein.The definitions include various examples and/or forms of components thatfall within the scope of a term and that can be used for implementation.The examples are not intended to be limiting. Further, the componentsdiscussed herein, can be combined, omitted or organized with othercomponents or organized into different architectures.

“Bus,” as used herein, refers to an interconnected architecture that isoperably connected to other computer components inside a computer orbetween computers. The bus can transfer data between the computercomponents. The bus can be a memory bus, a memory processor, aperipheral bus, an external bus, a crossbar switch, and/or a local bus,among others. The bus can also be a vehicle bus that interconnectscomponents inside a vehicle using protocols such as Media OrientedSystems Transport (MOST), Processor Area network (CAN), LocalInterconnect network (LIN), among others.

“Component”, as used herein, refers to a computer-related entity (e.g.,hardware, firmware, instructions in execution, combinations thereof).Computer components may include, for example, a process running on aprocessor, a processor, an object, an executable, a thread of execution,and a computer. A computer component(s) can reside within a processand/or thread. A computer component can be localized on one computerand/or can be distributed between multiple computers.

“Computer communication”, as used herein, refers to a communicationbetween two or more computing devices (e.g., computer, personal digitalassistant, cellular telephone, network device) and can be, for example,a network transfer, a file transfer, an applet transfer, an email, ahypertext transfer protocol (HTTP) transfer, and so on. A computercommunication can occur across, for example, a wireless system (e.g.,IEEE 802.11), an Ethernet system (e.g., IEEE 802.3), a token ring system(e.g., IEEE 802.5), a local area network (LAN), a wide area network(WAN), a point-to-point system, a circuit switching system, a packetswitching system, among others.

“Computer-readable medium,” as used herein, refers to a non-transitorymedium that stores instructions and/or data. A computer-readable mediumcan take forms, including, but not limited to, non-volatile media, andvolatile media. Non-volatile media can include, for example, opticaldisks, magnetic disks, and so on. Volatile media can include, forexample, semiconductor memories, dynamic memory, and so on. Common formsof a computer-readable medium can include, but are not limited to, afloppy disk, a flexible disk, a hard disk, a magnetic tape, othermagnetic medium, an ASIC, a CD, other optical medium, a RAM, a ROM, amemory chip or card, a memory stick, and other media from which acomputer, a processor or other electronic device can read.

“Database,” as used herein, is used to refer to a table. In otherexamples, “database” can be used to refer to a set of tables. In stillother examples, “database” can refer to a set of data stores and methodsfor accessing and/or manipulating those data stores. A database can bestored, for example, at a disk and/or a memory.

“Disk,” as used herein can be, for example, a magnetic disk drive, asolid-state disk drive, a floppy disk drive, a tape drive, a Zip drive,a flash memory card, and/or a memory stick. Furthermore, the disk can bea CD-ROM (compact disk ROM), a CD recordable drive (CD-R drive), a CDrewritable drive (CD-RW drive), and/or a digital video ROM drive (DVDROM). The disk can store an operating system that controls or allocatesresources of a computing device.

“Input/output device” (I/O device) as used herein can include devicesfor receiving input and/or devices for outputting data. The input and/oroutput can be for controlling different vehicle features which includevarious vehicle components, systems, and subsystems. Specifically, theterm “input device” includes, but it not limited to: keyboard,microphones, pointing and selection devices, cameras, imaging devices,video cards, displays, push buttons, rotary knobs, and the like. Theterm “input device” additionally includes graphical input controls thattake place within a user interface which can be displayed by varioustypes of mechanisms such as software and hardware based controls,interfaces, touch screens, touch pads or plug and play devices. An“output device” includes, but is not limited to: display devices, andother devices for outputting information and functions.

“Logic circuitry,” as used herein, includes, but is not limited to,hardware, firmware, a non-transitory computer readable medium thatstores instructions, instructions in execution on a machine, and/or tocause (e.g., execute) an action(s) from another logic circuitry, module,method and/or system. Logic circuitry can include and/or be a part of aprocessor controlled by an algorithm, a discrete logic (e.g., ASIC), ananalog circuit, a digital circuit, a programmed logic device, a memorydevice containing instructions, and so on. Logic can include one or moregates, combinations of gates, or other circuit components. Wheremultiple logics are described, it can be possible to incorporate themultiple logics into one physical logic. Similarly, where a single logicis described, it can be possible to distribute that single logic betweenmultiple physical logics.

“Memory,” as used herein can include volatile memory and/or nonvolatilememory. Non-volatile memory can include, for example, ROM (read onlymemory), PROM (programmable read only memory), EPROM (erasable PROM),and EEPROM (electrically erasable PROM). Volatile memory can include,for example, RAM (random access memory), synchronous RAM (SRAM), dynamicRAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM),and direct RAM bus RAM (DRRAM). The memory can store an operating systemthat controls or allocates resources of a computing device.

“Operable connection,” or a connection by which entities are “operablyconnected,” is one in which signals, physical communications, and/orlogical communications can be sent and/or received. An operableconnection can include a wireless interface, a physical interface, adata interface, and/or an electrical interface.

“Module”, as used herein, includes, but is not limited to,non-transitory computer readable medium that stores instructions,instructions in execution on a machine, hardware, firmware, software inexecution on a machine, and/or combinations of each to perform afunction(s) or an action(s), and/or to cause a function or action fromanother module, method, and/or system. A module can also include logic,a software controlled microprocessor, a discrete logic circuit, ananalog circuit, a digital circuit, a programmed logic device, a memorydevice containing executing instructions, logic gates, a combination ofgates, and/or other circuit components. Multiple modules can be combinedinto one module and single modules can be distributed among multiplemodules.

“Portable device”, as used herein, is a computing device typicallyhaving a display screen with user input (e.g., touch, keyboard) and aprocessor for computing. Portable devices include, but are not limitedto, handheld devices, mobile devices, smart phones, laptops, tablets ande-readers.

“Processor,” as used herein, processes signals and performs generalcomputing and arithmetic functions. Signals processed by the processorcan include digital signals, data signals, computer instructions,processor instructions, messages, a bit, a bit stream, that can bereceived, transmitted and/or detected. Generally, the processor can be avariety of various processors including multiple single and multicoreprocessors and co-processors and other multiple single and multicoreprocessor and co-processor architectures. The processor can includelogic circuitry to execute actions and/or algorithms.

“Vehicle,” as used herein, refers to any moving vehicle that is capableof carrying one or more human occupants and is powered by any form ofenergy. The term “vehicle” includes, but is not limited to cars, trucks,vans, minivans, SUVs, motorcycles, scooters, boats, go-karts, amusementride cars, rail transport, personal watercraft, and aircraft. In somecases, a motor vehicle includes one or more engines. Further, the term“vehicle” can refer to an electric vehicle (EV) that is capable ofcarrying one or more human occupants and is powered entirely orpartially by one or more electric motors powered by an electric battery.The EV can include battery electric vehicles (BEV) and plug-in hybridelectric vehicles (PHEV). The term “vehicle” can also refer to anautonomous vehicle and/or self-driving vehicle powered by any form ofenergy. The autonomous vehicle can carry one or more human occupants.Further, the term “vehicle” can include vehicles that are automated ornon-automated with pre-determined paths or free-moving vehicles.

“Vehicle display”, as used herein can include, but is not limited to,LED display panels, LCD display panels, CRT display, plasma displaypanels, touch screen displays, among others, that are often found invehicles to display information about the vehicle. The display canreceive input (e.g., touch input, keyboard input, input from variousother input devices, etc.) from a user. The display can be located invarious locations of the vehicle, for example, on the dashboard orcenter console. In some embodiments, the display is part of a portabledevice (e.g., in possession or associated with a vehicle occupant), anavigation system, an infotainment system, among others.

“Vehicle control system” and/or “vehicle system,” as used herein caninclude, but is not limited to, any automatic or manual systems that canbe used to enhance the vehicle, driving, and/or safety. Exemplaryvehicle systems include, but are not limited to: an electronic stabilitycontrol system, an anti-lock brake system, a brake assist system, anautomatic brake prefill system, a low speed follow system, a cruisecontrol system, a collision warning system, a collision mitigationbraking system, an auto cruise control system, a lane departure warningsystem, a blind spot indicator system, a lane keep assist system, anavigation system, a transmission system, brake pedal systems, anelectronic power steering system, visual devices (e.g., camera systems,proximity sensor systems), a climate control system, an electronicpretensioning system, a monitoring system, a passenger detection system,a vehicle suspension system, a vehicle seat configuration system, avehicle cabin lighting system, an audio system, a sensory system, aninterior or exterior camera system among others.

I. System Overview

The systems and methods described herein are generally directed tocontrolling a vehicle using a vehicle communication network that caninclude multiple vehicles and infrastructures. Communicating informationusing a vehicle communication network and/or sensing information allowsfor synergistic control of one or more vehicles in the context of atraffic scenario. In particular, the methods and systems describedherein provide Cooperative Adaptive Cruise Control (C-ACC), hazarddetection, and merge assistance using a vehicle communication network.FIG. 1A illustrates an exemplary traffic scenario 100 that will be usedto describe some of the systems and methods herein. The traffic scenario100 involves one or more vehicles on a roadway 102. The roadway 102 hasa first lane 104 a, a second lane 104 b, and a third lane 104 c. It isunderstood that the roadway 102 can have various configurations notshown in FIG. 1A, and can have any number of lanes.

In FIG. 1A, the traffic scenario 100 includes a host vehicle (HV) 106and one or more remote vehicles, which will generally be referred to asremote vehicles 108. However, more specifically, the remote vehicles 108include a remote vehicle (RV) 108 a, a remote vehicle 108 b, a remotevehicle 108 c, a remote vehicle 108 d, a remote vehicle 108 e, a remotevehicle 108 f, and a remote vehicle 108 g. The one or more remotevehicles 108 can also be referred to as a plurality of remote vehicles108. In some embodiments, one or more of the remote vehicles 108 can beidentified with respect to the host vehicle 106. For example, the remotevehicle 108 d can be identified as a preceding vehicle in relation tothe host vehicle 106. Specifically, the remote vehicle 108 d is apreceding vehicle located immediately in front or immediately ahead ofthe host vehicle 106. In some embodiments, one of the remote vehicles108 can be a leading vehicle, which is a remote vehicle ahead of a hostvehicle and a preceding vehicle. For example, in FIG. 1A a leadingvehicle can be identified as the remote vehicle 108 a, which is ahead ofthe host vehicle 106 and the preceding vehicle 108 d. In otherembodiments, the leading vehicle can be the remote vehicle 108 b.

In some embodiments, one or more of the remote vehicles 108 in thetraffic scenario 100 can be identified as a platoon of vehicles 108. Forexample, the host vehicle 106, the remote vehicle 108 a, the remotevehicle 108 b, the remote vehicle 108 c, and the remote vehicle 108 dcan be part of a platoon of vehicles 108 travelling in the same lane(i.e., the second lane 104 b). FIG. 1B is a schematic view of the remotevehicles 108 travelling in the second lane 104 b of FIG. 1A, namely, thehost vehicle 106, the remote vehicle 108 a, the remote vehicle 108 b,the remote vehicle 108 c, and the remote vehicle 108 d. In someembodiments, the string of vehicles shown in FIG. 1B can be a platoon ofvehicles 108. It is understood that the host vehicle 106 and the remotevehicles 108 can be in different configurations and positions other thanthose shown in FIGS. 1A and 1B.

In the systems and methods discussed herein, the host vehicle 106 can becontrolled, in part, based on data about the one or more remote vehicles108 communicated via a vehicle communication network. The host vehicle106 and one or more of the remote vehicles 108 can communicate as partof a vehicle communication network. In particular, the vehiclecommunication described herein can be implemented using Dedicated ShortRange Communications (DSRC).

However, it is understood that the vehicle communication describedherein can be implemented with any communication or network protocol,for example, ad hoc networks, wireless access within the vehicle,cellular networks, Wi-Fi networks (e.g., IEEE 802.11), Bluetooth, WAVE,CALM, among others. Further, the vehicle communication network can bevehicle-to-vehicle (V2V) or a vehicle-to-everything (V2X).

In FIG. 1A, the host vehicle 106 can transmit, receive, and/or exchangecommunications including data, messages, images, and/or otherinformation with other vehicles, user, or infrastructures, using DSRC.In particular, the host vehicle 106 is equipped with avehicle-to-vehicle (V2V) transceiver 110 that can exchange messages andinformation with other vehicles, users, or infrastructures that areoperable for computer communication with the host vehicle 106. Forexample, the V2V transceiver 110 can communicate with the remote vehicle108 a via a V2V transceiver 112 a, the remote vehicle 108 b via a V2Vtransceiver 112 b, the remote vehicle 108 c via a V2V transceiver 112 c,and the remote vehicle 108 g via a V2V transceiver 112 d. The V2Vtransceiver 110 can also communicate with a wireless network antenna 114and/or a roadside equipment (RSE) 116. Similarly, the remote vehicle 108a, the remote vehicle 108 b, the remote vehicle 108 c, and the remotevehicle 108 g can use its respective V2V transceiver to communicate withone another, the host vehicle 106, the wireless network antenna 114,and/or the RSE 116. In the embodiment shown in FIG. 1A, the remotevehicle 108 d, the remote vehicle 108 e, and the remote vehicle 108 fare not equipped (e.g., do not have DSRC V2V transceivers) forcommunication with the host vehicle 106 using the vehicle communicationnetwork. It is understood that in other embodiments, one or more of theremote vehicle 108 d, the remote vehicle 108 e, and the remote vehicle108 f can include equipment for communication with the host vehicle 106using the vehicle communication network.

As will be discussed herein, various types of data can be communicatedusing the vehicle communication network. For example, the type and/orspecifications of the vehicle, navigation data, roadway hazard data,traffic location data, course heading data, course history data,projected course data, kinematic data, current vehicle position data,range or distance data, speed and acceleration data, location data,vehicle sensory data, vehicle subsystem data, and/or any other vehicleinformation. Some of the embodiments discussed herein include exchangingdata and information between networked vehicles for use in vehicledriving. More specifically, control of a vehicle can be executed basedin part on the communicated data. Accordingly, DSRC communication can beused to control one or more vehicle control systems. Vehicle controlsystems include, but are not limited to, cooperative adaptive cruisecontrol (C-ACC) systems, adaptive cruise control (ACC) systems,intelligent cruise control systems, autonomous driving systems,driver-assist systems, lane departure warning systems, merge assistsystems, freeway merging, exiting, and lane-change systems, collisionwarning systems, integrated vehicle-based safety systems, and automaticguided vehicle systems. Some of the embodiments herein are described inthe context of a C-ACC system, a vehicle control system, and/or a mergeassist system.

Additionally, in the systems and methods discussed herein, the hostvehicle 106 can be controlled, in part, based on data about the one ormore remote vehicles 108 sensed by the host vehicle 106. In FIG. 1A,each of the remote vehicles 108 on the roadway 102 can sense proximatevehicles and objects, which is illustrated by the accurate linesemanated from the remote vehicles 108. The remote vehicles 108 can senseproximate vehicles and objects using one or more sensors (e.g., radarsensors). The host vehicle 106 can include one or more sensors, whichwill be discussed in further detail herein, for sensing data about othervehicles and objects in proximity to the host vehicle 106. For example,the host vehicle 106 can sense distance, acceleration, and velocityabout the preceding vehicle 108 d or other vehicles proximate to thehost vehicle 106. Accordingly, although the preceding vehicle 108 d isnot equipped for V2V communication with the host vehicle 106, the hostvehicle 106 can still obtain data about the preceding vehicle 108 dusing on-board sensors.

A. Vehicle Communication Network

Referring now to FIG. 2, a schematic view of a vehicle communicationnetwork 200 according to an exemplary embodiment is shown. The vehiclecommunication network 200 can be implemented within the vehicles shownin FIGS. 1A and 1B. In FIG. 2, the host vehicle 106 includes a C-ACCsystem 202. The C-ACC system 202 can exchange vehicle and traffic datawith other DSRC compatible vehicles via V2V transceiver 110. Forexample, the V2V transceiver 110 can exchange data with the remotevehicle 108 a via the V2V transceiver 112 a using a communication link203. Although only one remote vehicle is shown in FIG. 2, it isunderstood that the host vehicle 106 can communicated with more than oneremote vehicle configured for DSRC communication within the vehiclecommunication network 200. Thus, is some embodiments, communicationlinks using DSRC can be established between the host vehicle 106 and aplurality of remote vehicles (e.g., the remote vehicles 108) configuredfor V2V communication using DSRC.

In the embodiments discussed herein, control of the host vehicle 106 isexecuted based on information communicated directly between the hostvehicle 106 and one or more of the remote vehicles 108. However, in someembodiments, data can be exchanged with other infrastructures andservers. For example, in FIG. 2, the C-ACC system 202 can transmit andreceive information directly or indirectly to and from a serviceprovider 212 over a wireless communication network 204. The serviceprovider 212 can include a remote server 214, a remote transmitter 216,a remote receiver 218, and a remote memory 220 that are configured to bein communication with one another. In one embodiment, the host vehicle106 can receive data and information from the service provider 212 byway of a one-to-many communication network 222. The one-to-manycommunication network 222 can include systems that can send informationfrom one source to a plurality of receivers. Examples of one-to-manycommunication networks can include television, radio, satellitenetworks, among others.

In FIG. 2, the V2V transmitter 110 can be used by the C-ACC system 202to receive and transmit information to and from the service provider 212and other information providers through the wireless communicationnetwork 204 and a broadband network 210, such as the Internet. Inalternative embodiments, a radio frequency (RF) transceiver 224 in hostvehicle 106 can be used by the C-ACC system 202 to receive and transmitinformation to and from the service provider 212 through wirelessnetwork antenna 114 to the wireless communication network 204. The RFtransceiver 224 can include, but is not limited to, a wireless phone, awireless modem, a Wi-Fi compatible transceiver, and/or any other devicethat communicates with other networks using the wireless communicationnetwork 204. The host vehicle 106 can also receive and transmitinformation to and from a traffic data supplier 206 and/or one or moreother information suppliers 208. This information can include, but isnot limited to, traffic data, vehicle location and heading data,high-traffic event schedules, weather data, or other transport relateddata, etc. The traffic data supplier 206 and the other informationsupplier 208 can communicate with the service provider 212 through thebroadband network 210.

In some embodiments, the service provider 212 can be linked to multiplevehicles through a network connection, such as via the wireless networkantenna 114 (FIG. 1A), and/or other network connections. Further, anyother wireless communication system capable of delivering data may beused such as satellite, cellular, Wi-Fi, microwave, etc. The serviceprovider 212 may also be linked by a wired connection, such as broadbandcable or fiber optic connections, Ethernet, DSL, ADSL, telephone modems,and/or any other wired communication system capable of delivering datato traffic infrastructure such as RSE 116.

B. Vehicle System and C-ACC Overview

The host vehicle 106 and the C-ACC system 202 will now be described inmore detail with reference to FIG. 3. FIG. 3 is a block diagram of anexemplary control system 300 of the host vehicle 106. However, thecomponents and functionalities shown in FIG. 3 can be associated withother vehicles. For example, the remote vehicles 108 can include one ormore of the components and functionalities of the control system 300.Thus, the control system 300 can be alternatively use the system byother entities or in other applications. Further, in some embodiments,the control system 300 will be referred to as a C-ACC control system(e.g., the C-ACC system 202). Other C-ACC systems associated with somevehicles may include different elements and/or arrangements asconfigured to the C-ACC system 202, but can be configured to communicateover the vehicle communication network 200 with one or more other C-ACCsystems, vehicle control systems, or merge assist systems.

The host vehicle 106 can have one or more computers and or computingdevices, for example, in FIG. 3, the control system 300 includes avehicle computer system 302. In some embodiments discussed herein, thevehicle computer system 302 will be referred to as a C-ACC computersystem 302. In other embodiments, the vehicle computer system 302 can beassociated with another type of vehicle control system or can be ageneral vehicle computing device that facilitates the functionsdescribed herein.

The vehicle computer system 302 includes a processor 304 and a memory306. In some embodiments, the vehicle computer system 302 may includeprogrammable logic circuits and/or pre-configured logic circuits forexecuting C-ACC system functions and/or merge assist system functions.The memory 306 stores information accessible by the processor 304including instructions 308 and data 310 that may be executed orotherwise used by the processor 304. The control logic (in this example,software instructions or computer program code), when executed by theprocessor 304, causes processor 304 to perform the functions of theembodiments as described herein. The memory 306 may be of any typecapable of storing information accessible by the processor 304,including a computer-readable medium, or other medium that stores datathat may be read with the aid of an electronic device, such as ahard-drive, flash drive, memory card, ROM, RAM, DVD or other opticaldisks, as well as other write-capable and read-only memories. Systemsand methods may include different combinations of the foregoing, wherebydifferent portions of the instructions and data are stored on differenttypes of media.

The instructions 308 may be any set of instructions to be executeddirectly (such as machine code) or indirectly (such as scripts) by theprocessor 304. For example, the instructions may be stored as computercode on the computer-readable medium. In this regard, the terms“instructions” and “programs” may be used interchangeably herein. Theinstructions may be stored in object code format for direct processingby the processor 304, or in any other computer language includingscripts or collections of independent source code modules that areinterpreted on demand or compiled in advance. Functions, methods androutines of the instructions are explained in more detail below.

The data 310 may be retrieved, stored or modified by the processor 304in accordance with the instructions 308. For instance, although thevehicle computer system 302 is not limited by any particular datastructure, the data 310 may be stored in computer registers, in arelational database as a table having a plurality of different fieldsand records, XML documents or flat files. The data 310 may also beformatted in any computer-readable format. The data 310 may include anyinformation sufficient to identify the relevant information, such asnumbers, descriptive text, proprietary codes, references to data storedin other areas of the same memory or different memories (including othernetwork locations) or information that is used by a function tocalculate the relevant data.

In FIG. 3, the data 310 can include traffic data 312, map component data314, traffic assist data 316, and merge models 318. The traffic data 312can include commercially-available databases of transport data, trafficdata, and traffic schedules, among others. The map component data 314can include maps identifying the shape and elevation of roadways, lanelines, intersections, crosswalks, bicycle lanes, school zones, speedlimits, traffic signals, buildings, signs, real time trafficinformation, or other transport information that can be used byvehicles. For example, the map component data 314 may include one ormore mapped networks of information, such as roadways, lanes,intersections, and the connections between these features. Each featuremay be stored as map component data 314, and may be associated withinformation, such as a geographic location, and whether or not it islinked to other related features, e.g., dimensions of a widened mergelane may be linked to a roadway location and an entrance ramp, amongothers. The traffic assist data 316, which will be discussed in furtherdetail herein, can include traffic data from various sources within andexternal to host vehicle 106. Further, the merge models 318 can includetypes of merge scenarios for merge assistance as will be discussed belowin Section IV.

The vehicle computer system 302 can communicate with various componentsof the host vehicle 106. For example, the vehicle computer system 302can communicate with the vehicle electronic control unit (ECU) 320, andcan send and receive information from the various systems of hostvehicle 106, for example vehicle sensor systems 322, a vehiclecommunication system 324, a vehicle navigation system 326, and a vehicleinterface system 328. When engaged, the vehicle computer system 302 cancontrol some or all of these functions of host vehicle 106. It isunderstood that, although various systems and vehicle computer system302 are shown within host vehicle 106, these elements may be external tohost vehicle 106 and/or physically separated by large distances.Further, the vehicle computer system 302 can be operable connected forcomputer communication to other components of the host vehicle 106 via,for example, a bus 330.

The vehicle sensor system 322 includes various vehicle sensors thatsense and/or measure data internally and/or externally from the hostvehicle 106. More specifically, the vehicle sensor system 322 caninclude vehicle sensors for sensing and measuring a stimulus (e.g., asignal, a property, a measurement, a quantity) associated with the hostvehicle 106 and/or a particular vehicle system of the host vehicle 106.In some embodiments, the vehicle sensors are for sensing and measuring astimulus associated with a vehicle and/or an object in proximity to thehost vehicle 106. The vehicle sensor system 322 and the various vehiclesensors will be discussed in more detail herein with FIG. 4.

As indicated above, the host vehicle 106 may also include the vehiclecommunication system 324. The vehicle computer system 302 cancommunicate with external communication apparatus for sending andreceiving data. For instance, the vehicle communication system 324includes the V2V transceiver 110 that can communicate with compatibleDSRC transceivers in the vehicle communication network 200. As describedpreviously in relation to FIG. 2, the vehicle communication system 324can include the RF transceiver 224 for communicating wirelessly toservice provider 212 through wireless communication network 204. It isunderstood that some vehicles may not be equipped with communicationequipment for V2V and/or V2X communication using DSRC or another type ofcommunication protocol. For example, the remote vehicle 108 d, theremote vehicle 108 e, and the remote vehicle 108 f shown in FIG. 1A arenot equipped with a V2V transceiver that can communicate with compatibleDSRC transceivers in the vehicle communication network 200.

The host vehicle 106 also includes the vehicle navigation system 326.The vehicle navigation system 326 can provide navigation maps andinformation to the host vehicle 106 and/or the vehicle computer system302. The vehicle navigation system 436 may be any type of known, relatedor later developed navigational system and may include a GPS unit (notshown). The phrase “navigation information” refers to any informationthat can be used to assist host vehicle 106 in navigating a roadway orpath. Navigation information may include traffic data, map data, androadway classification information data. Examples of navigationinformation can include street addresses, street names, street oraddress numbers, intersection information, points of interest, parks,bodies of water, any political or geographical subdivision includingtown, township, province, prefecture, city, state, district, ZIP orpostal code, and country. Navigation information can also includecommercial information including business and restaurant names,commercial districts, shopping centers, and parking facilities.Navigation information can also include geographical information,including information obtained from any Global Navigational Satelliteinfrastructure (GNSS), including Global Positioning System or Satellite(GPS), Glonass (Russian) and/or Galileo (European).

Further, the host vehicle 106 includes a vehicle interface system 328that can be used to receive input from a user and/or provide feedback tothe user. Accordingly, the vehicle interface system 328 can include adisplay portion and an input portion. In some embodiments, the vehicleinterface system 328 is a human machine interface (HMI) and/or aheads-up display (HUD) located in the host vehicle 106. The vehicleinterface system 328 can receive one or more user inputs from one ormore users (e.g., a driver, vehicle occupants). The input portion of thevehicle interface system 328 may enable a user, such as a driver orvehicle occupant, to interact with or provide input, such as user input,gestures, clicks, points, selections, voice commands, etc. the hostvehicle 106 and/or the vehicle computer system 302. For example, in someembodiments a user can enable the vehicle computer system 302 and/orcontrol features of the vehicle computer system 302 by interacting withthe vehicle interface system 328.

As an example, the input portion of the vehicle interface system 328 canbe implemented as a touch screen, a touchpad, a track pad, one or morehardware buttons (e.g., on a radio or a steering wheel), one or morebuttons, such as one or more soft buttons, one or more software buttons,one or more interactive buttons, one or more switches, a keypad, amicrophone, one or more sensors, etc. In one or more embodiments, thevehicle interface system 328 can be implemented in a manner whichintegrates a display portion such that the vehicle interface system 328both provides an output (e.g., renders content as the display portion)and receives inputs (e.g., user inputs). An example of this can be atouch screen. Other examples of input portions may include a microphonefor capturing voice input from a user.

The vehicle interface system 328 can display information (e.g.,graphics, warnings, and notifications). For example, the vehiclecomputer system 302 can generate information, suggestions, warnings,and/or alerts and provide the same to a vehicle operator on a displaydevice (e.g., display portion) of the vehicle interface system 328. Theinformation, warnings, etc., can include, but are not limited to, one ormore navigation maps, symbols, icons, graphics, colors, images,photographs, videos, text, audible information, among others. Thevehicle interface system 328 can also include other systems that providevisual, audible, and/or tactile/haptic feedback to a user. For example,an active force pedal (AFP) can be included as part of an accelerationpedal in the host vehicle 106 to provide active feedback force to adriver's foot as the driver pushes the acceleration pedal.

The host vehicle 106 may include other apparatus for communicating, andin some cases controlling, the various components associated withvehicle systems. The various vehicle systems that the host vehicle 106can control and/or communicate with will now be discussed in greaterdetail with reference to FIG. 4. FIG. 4 is a schematic view of the hostvehicle 106 including vehicle systems and components that can be thatcan be associated with the vehicle control system 300 of FIG. 3. Asmentioned above with FIG. 3, the components and functionalities shown inFIG. 4 can be associated with other vehicles. For example, the remotevehicles 108 can include one or more of the components andfunctionalities shown in FIG. 4.

In FIG. 4, the ECU 320 can communicate with a data logger system 402,one or more vehicle systems 404, the vehicle navigation system 326, thevehicle sensor system 322, the vehicle V2V transceiver 110, the RFtransceiver 224, a camera 416 and a laser 418. In some embodimentsdiscussed herein, the ECU 320 is configured to receive instructions fromthe vehicle computer system 302 to retrieve data from one or morecomponents shown in FIG. 4. For example, the ECU 320 can receiveinstructions from the C-ACC computer system 302 for commands to activateor suppress a particular vehicle system 404, for example, a brake oraccelerator, according to an acceleration control rate.

The data logger system 402 can communicate with the ECU 320 to acquireand log data collected from any of the vehicle systems 404 and/or thevehicle sensor system 416. As discussed above, the host vehicle 106 caninclude the vehicle navigation system 326 that is configured to be incommunication with the ECU 320. The navigation system 326 can include aGPS receiver 406, a navigation system display 408 (e.g., part of thevehicle interface system 328), and can store map and locationinformation in a navigation database 410. The navigation system display408 can display navigational maps and information to a user using anytype of display technology. The navigation system display 408 may alsocommunicate information to the host vehicle 106 using any type of known,related art or later developed audio technology, such as by usingpredetermined sounds or electronically generated speech.

As mentioned above, the vehicle sensor system 322 can include variousvehicle sensors and can communicate with the ECU 320 and any number ofvehicle sensor devices in any configuration. The vehicle sensor system322 devices can be advantageous by collecting data for identificationand tracking the movement of traffic entities such as the remotevehicles 108, vehicular traffic, or any other condition, entity, orvehicle that could provide data. It is understood that the vehiclesensors can be any sensor used in any vehicle system for detectingand/or sensing a parameter of that system. Exemplary vehicle sensorsinclude, but are not limited to: acceleration sensors, speed sensors,braking sensors, proximity sensors, vision sensors, seat sensors,seat-belt sensors, door sensors, environmental sensors, yaw ratesensors, steering sensors, GPS sensors, among others.

It is also understood that the vehicle sensors can be any type ofsensor, for example, acoustic, electric, environmental, optical,imaging, light, pressure, force, thermal, temperature, proximity, amongothers. The vehicle sensors could be disposed in one or more portions ofthe host vehicle 106. For example, the vehicle sensors could beintegrated into a dashboard, seat, seat belt, door, bumper, front, rear,corners, dashboard, steering wheel, center console, roof or any otherportion of the host vehicle 106. In other cases, however, the vehiclesensors could be portable sensors worn by a driver (not shown),integrated into a portable device (not shown), carried by the driver(not shown), integrated into an article of clothing (not shown) worn bythe driver or integrated into the body of the driver (e.g. an implant)(not shown).

Referring now to the exemplary vehicle sensors in FIG. 4, the vehiclesensor system 322 can include a sensor 412, a radar system 414, thecamera 416, and the laser 418, each of which can be disposed at anybeneficial area of the host vehicle 106. Although one sensor 418 isshown in FIG. 4, it is understood that sensor 418 is a representation ofone or more sensors installed within or outside of the host vehicle 106.In some embodiments, the vehicle sensor 418 sense vehicle speed,acceleration rate, braking rate, and other vehicle dynamics data aboutthe host vehicle 106. In some embodiments, the vehicle sensor 418 cancollect proximity data using rear, front, and side proximity detectionsensors 418.

The radar system 414 can include a front long range radar and/or a frontmid-range radar. The front long range radar can measure distance (e.g.,lateral, longitudinal) and speed of objects surrounding the host vehicle106. For example, the front long range radar can measure distance andspeed of one or more of the remote vehicles 108 surrounding the hostvehicle 106. In some embodiments, the radar system 414 can include aplurality of radars in different location of the host vehicle 106. Forexample, a front left radar located at a front left corner area of thehost vehicle 106, a front right radar located at a front right cornerarea of the host vehicle 106, a rear left radar located at a rear leftcorner area of the host vehicle 106, and a rear right radar located at arear right corner area of the host vehicle 106.

FIG. 4 also shows the V2V transceiver 110 of the host vehicle 106 forcommunicating with other V2V compatible vehicles. In an embodiment, V2Vtransceiver 110 can collect traffic data from other DSRC transceiversthat can be configured for a vehicle, pedestrian, bicycle, building,tower, billboard, traffic signal, roadway sign, or any transport relatedentity or user. A display operationally connected to a DSRC transceivercan also display any messages, maps, vehicle locations, data, images,alerts, and warnings transmitted to or received from DSRC users invehicle communication network 200. A communication link (e.g., thecommunication link 203 in FIG. 2) between DSRC transceivers may beinitiated by any user. In the embodiments, a DSRC transceiver maycontinuously search for signals from other DSRC transceivers, such as byemitting a periodic signal that searches for a reply. In otherembodiments, a DSRC transceiver may emit periodic signals searching fora reply from an in-range DSRC transceiver. If a DSRC transceiverreplies, then a communications link may be established. Information anddata received by the host vehicle 106 can be saved to data logger system402 and/or the data 310 and processed by the vehicle computer system302.

An exemplary interior view of the host vehicle 106 is shown in FIG. 5.Specifically, FIG. 5 is a schematic of an exemplary design of a vehicleinterior 500 associated with the host vehicle 106 and the vehiclecontrol system 300 of FIG. 3. The vehicle interior 500 may include, forexample, a dashboard 502, a steering apparatus such as a steering wheel504, an instrument panel 506, and a center portion 508. The centerportion 508 can include one or more devices associated with the interiorof the vehicle, including but are not limited to: audio devices, videodevices, navigation devices, as well as any other types of devices. Inaddition, the center portion 508 can be associated with controls for oneor more systems of the host vehicle 106 including, but not limited to:climate control systems, radio and sound systems, and other types ofsystems.

The host vehicle 106 may also have a display device 510, which can bepart of the vehicle interface system 328 for displaying information fromthe vehicle control system 300, and/or other related or unrelatedvehicular systems. Examples of display device 510 include, but are notlimited to, LCDs, CRTs, ELDs, LEDs, OLEDs, or electronic paper displayseach with or without a touchscreen, as well as other types of displays.The display device 510 can include a touchscreen for use as a user inputdevice for the vehicle interface system 328. For example, using thevehicle interface system 328 a user can activate or deactivate one orC-ACC system modes, merge assist modes, and for enabling a user toprovide information, such as navigation destination or trafficinformation, to the vehicle computer system 302.

In alternative embodiments, the vehicle interface system 328 can includebuttons, a keypad, or other types of input devices. In anotherembodiment, the vehicle interface system 328 can include a heads upprojection (HUD) type display that is configured to project an imageonto one or more surfaces of the host vehicle 106, such as windshield512. In some embodiments, the display device 510 can be located in anyportion of the host vehicle 106, or can be a portable device (notshown). For example, display device 510 can be located within instrumentpanel 506.

In addition, as discussed above with FIG. 3, the display device 510 canbe configured to present visual information for the vehicle computersystem 302 and other devices or systems within the host vehicle 106,such as the vehicle navigation system 326. For example, vehicleinterface system 328 can inform a driver with visual or auditory alertsor information of traffic flow, hazard detection, a predicted trafficmerge by another vehicle, among others. For example, the display device510 can be configured to display hazard alerts, merge alerts, andtraffic data related to one or more of the remote vehicles 108 when oneor more of the remote vehicles 108 would affect the operation of thehost vehicle 106. Additionally in FIG. 5, an acceleration pedal 514 anda brake pedal 516 are shown. As discussed above, in some embodiments,the acceleration pedal 514 can include an active force pedal (AFP) thatcan provide active feedback force to a driver's food as the driverpushes the acceleration pedal 514.

C. C-ACC Control Model

As mentioned above, in some embodiments, the systems and methodsdiscussed herein control the host vehicle 106 using data about the hostvehicle 106 and data about one or more of the remote vehicles 108. Thedata about one or more of the remote vehicles 108 can be received by theC-ACC control system 300 using the vehicle communication network 200. Insome embodiments, the data about one or more of the remote vehicles 108can be received by the C-ACC control system 300 using sensors (e.g.,radar sensors) on-board the host vehicle 106. Fusion and analysis ofthis data can be used to control the host vehicle 106 thereby allowingthe host vehicle 106 to preemptively react to a traffic scenario and oneor more of the remote vehicles 108 that may affect the operation or thetravel path of the host vehicle 106. Exemplary control by the C-ACCcontrol system 300 will now be described in greater detail.

In some of the embodiments discussed herein, motion of the host vehicle106 can be controlled, for example, by the C-ACC control system 300. Inparticular, the C-ACC control system 300 can control longitudinal motionof the host vehicle 106 using the data discussed above. For example, theC-ACC control system 300 can control acceleration and/or deceleration bygenerating an acceleration control rate and/or modifying a currentacceleration control rate (e.g., a target acceleration rate). By usingthe data discussed above, the C-ACC control system 300 can assess adynamic state of the host vehicle 106 and the remote vehicles 108 andaccordingly adapt control of the host vehicle 106. Referring now to FIG.6, a schematic C-ACC control model 600 for controlling a vehicle controlsystem is shown. FIG. 6 will be described with reference to thecomponents of FIGS. 2-5. The control model 600 receives as inputs hostvehicle data 602, V2V remote vehicle data 604, and sensed remote vehicledata 606. The host vehicle data 602 includes vehicle dynamics data aboutthe host vehicle 106. For example, speed, acceleration, velocity, yawrate, steering angle, throttle angle, range or distance data, amongothers. The host vehicle data 602 can be accessed from the vehiclesensor system 322 via the bus 330. The host vehicle data 602 can alsoinclude status information about different vehicle systems. For example,the host vehicle data 602 can include turn signal status, course headingdata, course history data, projected course data, kinematic data,current vehicle position data, and any other vehicle information aboutthe host vehicle 106.

The V2V remote vehicle data 604 includes remote vehicle dynamics dataabout one or more of the remote vehicles 108 communicated via thevehicle communication network 200. The V2V remote vehicle data 604 caninclude speed, acceleration, velocity, yaw rate, steering angle, andthrottle angle, range or distance data, among others, about one or moreof the remote vehicles 108. The V2V remote vehicle data 604 can alsoinclude course heading data, course history data, projected course data,kinematic data, current vehicle position data, and any other vehicleinformation about the remote vehicle 108 that transmitted the V2V remotevehicle data 604.

The sensed remote vehicle data 606 can include data about one or more ofthe remote vehicles 108 and/or other objects in proximity to the hostvehicle 106, received and/or sensed by the vehicle system sensors 322.For example, in the embodiments discussed herein, the sensed remotevehicle data 606 includes vehicle data obtained from the radar system414 including proximity data. For example, the sensed remote vehicledata 606 can include distance and speed of one or more of the remotevehicles 108 surrounding the host vehicle 106.

The host vehicle data 602, the V2V remote vehicle data 604, and thesensed remote vehicle data 606 can be input to the C-ACC computer system302 and processed using a control algorithm, which will be described infurther detail herein. The C-ACC computer system 302 can outputacceleration and/or deceleration commands to the ECU 320, which thenexecutes said commands to the respective vehicle system, for example, abrake actuator 608 (e.g., that can be part of a brake assist system)and/or a throttle actuator 610. For example, based on the host vehicledata 602, the V2V remote vehicle data 604, and the sensed remote vehicledata 606, the C-ACC computer system 302 can generate an accelerationcontrol rate, which can be a target acceleration rate for the hostvehicle 106. Based on the current acceleration rate of the host vehicle106, the C-ACC computer system 302 can generate a control signal toachieve the acceleration control rate. The control signal can be sent tothe ECU 320, which then executes the signal, for example, by controllingthe brake actuator 608 and/or the throttle actuator 610.

Additionally, the C-ACC computer system 302 and/or the ECU 320 canexecute commands to the HMI 612 (e.g., the vehicle interface system328). For example, based on the host vehicle data 602, the V2V remotevehicle data 604, and the sensed remote vehicle data 606, visual,audible and/or tactile feedback can be generated and provided via theHMI 612. Accordingly, the host vehicle 106 is controlled based on thefusion of the host vehicle data 602, the V2V remote vehicle data 604,and the sensed remote vehicle data 606 in accordance with the controlalgorithm, which will now be described in further detail.

The C-ACC computer system 302 implements a control algorithm to generatean acceleration control rate that can be used to control the hostvehicle 106 in relation to one or more of the remote vehicles 108,namely, a preceding vehicle and a leading vehicle. For example, withreference to FIG. 1B, the host vehicle 106 can be controlled in relationto the leading vehicle 108 a and the preceding vehicle 108 d. Thecontrol algorithm can include a distance control component based on therelative distance between the host vehicle 106 and the preceding vehicle108 d and a headway reference distance. The distance control componentcan be expressed mathematically as:a _(x) _(ref) =K _(p)(x _(i−1) −x _(i) −h{dot over (x)} _(i) −L_(PV))  (1)where x_(i−1) is a distance from a rear end of the host vehicle 106 tothe front end of the preceding vehicle 108 d, x_(i) is a length of thehost vehicle 106, h{dot over (x)}_(i) is a pre-determined headwayreference distance and L_(PV) is the length of the preceding vehicle 108d. These variables are schematically shown in FIG. 1B. The controlalgorithm can also include a velocity control component based on therelative velocity between the host vehicle 106 and the preceding vehicle108 d. Accordingly, in one embodiment, the velocity control componentcan be expressed mathematically as:a _(x) _(ref) =K _(v)(v _(i−1) −v ₁)  (2)where v_(i−1) is a velocity of the preceding vehicle 108 d, v_(i) is thevelocity of the host vehicle 106, and K_(v) is a vehicle speed dynamicgain coefficient. In some embodiments, the acceleration control rate iscalculated based on the distance control component and the velocitycontrol component, which can be expressed mathematically as:a _(xv) _(ref) =K _(p)(x _(i−1) −x _(i) −h{dot over (x)} _(i) −L_(PV))+K _(v)(v _(i−1) −v _(i))  (3)

In one embodiment, an acceleration control reference based onacceleration data communicated via the vehicle communication network 200can be calculated and used as a feedforward control input to theacceleration control reference based on the distance component and thevelocity component discussed above in equation (3). More specifically,in one embodiment, the control algorithm includes an accelerationcontrol component based on acceleration data of the leading vehicle 108a and acceleration data of the preceding vehicle 108 d. The accelerationdata about the leading vehicle 108 a is V2V remote vehicle data receivedusing the vehicle communication network 200 (e.g., via DSRC). In oneembodiment, the acceleration data about the preceding vehicle 108 d issensed remote vehicle data received using sensors on-board the hostvehicle 106, for example, the radar system 414. Accordingly, in oneembodiment, the acceleration control reference based on accelerationdata communicated via the vehicle communication network can be expressedmathematically as:a _(DSRC) _(ref) =K _(a) _(PV) ·a _(i−1) +K _(dsrc) ·a _(L)  (4)where a_(i−1) is an acceleration rate of the preceding vehicle 108 ddetected by the radar system 414, K_(a) _(PV) is a preceding vehicleacceleration dynamic gain coefficient, a_(L) is an acceleration rate ofthe leading vehicle 108 a received by the host vehicle 106 from theleading vehicle 108 a using DSRC via the vehicle communication network200, and K_(dsrc) is a leading vehicle acceleration dynamic gaincoefficient. In the examples discussed herein, the acceleration rate ofthe preceding vehicle 108 d is sensed remote vehicle data 606 (e.g.,radar data detected using radar sensors), but it is understood that inother embodiments the acceleration rate of the preceding vehicle 108 dcan be V2V remote vehicle data received by the host vehicle 106 usingDSRC via the vehicle communication network 200. Based on the above, anacceleration control rate can be generated by the C-ACC computer system302 using the distance component, the velocity component, theacceleration component of the preceding vehicle 108 d, and theacceleration component of the leading vehicle 108 a. This can beexpressed mathematically as,a _(ref) =K _(p)(x _(i−1) −x _(i) −h{dot over (x)} _(i) −L _(PV))+K_(v)(v _(i−1) −v _(i))+K _(a) _(PV) ·a _(i−1) +K _(dsrc) ·a _(L)  (5)

As mentioned above, the C-ACC computer system 302 can implement a feedforward control algorithm to generate the acceleration control rate tocontrol the host vehicle 106 based on the equations discussed above.Referring now to FIG. 7 a block diagram of an exemplary control system700 of the C-ACC computer system 302 according to the control algorithmdiscussed above is shown. In FIG. 7, the control system 700 includes afeedforward control system 702 used as input to a C-ACC control system704. The feedforward control system 702 receives as inputs anacceleration rate of the leading vehicle 108 a received using DSRC viathe vehicle communication network 200, and an acceleration rate of thepreceding vehicle 108 d received using the radar system 414. The inputsare modified by a dynamic gain, namely, the leading vehicle accelerationdynamic gain coefficient, to generate an acceleration reference signala_(DSRC) _(ref) , which is received as input by the C-ACC control system704. The C-ACC control system 704 determines the distance component andthe velocity component as discussed above with equations (1)-(3) and cancalculates an acceleration control rate using the input received fromthe feedforward control system 702.

II. Methods for C-ACC Control

Referring now to FIG. 8, a method 800 for controlling a host vehiclehaving a vehicle control system using vehicular communication will nowbe described according to an exemplary embodiment. FIG. 8 will also bedescribed with reference to FIG. 1A, 1B and FIGS. 2-7. In oneembodiment, the method 800 is for controlling the host vehicle 106having a vehicle control system (e.g., the C-ACC computer system 302)that controls motion of the host vehicle 106 relative to the precedingvehicle 108 d. As shown in FIGS. 1A and 1B, the preceding vehicle 108 dis positioned immediately ahead of the host vehicle 106. At block 802,the method 800 includes receiving remote vehicle data about one or moreremote vehicles. More specifically, in one embodiment, block 802includes receiving V2V remote vehicle data 604 transmitted from one ormore remote vehicles 108 to the host vehicle 106 via a vehicularcommunication network 200 and one or more communication links betweenthe host vehicle 106 and each of the one or more remote vehicles 108. Insome embodiments, V2V remote vehicle data 604 is received from one ormore remote vehicles 108 within a predetermine distance (e.g., 300 m)from the host vehicle 106. As discussed above with FIGS. 1A, 1B, and 2,the host vehicle 106 is equipped with the V2V transceiver 110 that cancommunicate with other remote vehicles 108 operable for V2Vcommunication on the roadway 102. For example, the V2V transceiver 110can communicate with the remote vehicle 108 a via a V2V transceiver 112a, the remote vehicle 108 b via a V2V transceiver 112 b, the remotevehicle 108 c via a V2V transceiver 112 c, and the remote vehicle 108 gvia a V2V transceiver 112 d.

To facilitate communication, a communication link is established betweenthe host vehicle 106 and the one or more remote vehicles 108 operablefor V2V communication on the roadway 102. The communication link can beestablished between V2V transceivers. For example, the V2V transceiver110 can continuously search for signals from other V2V transceivers,such as by emitting a periodic signal that searches for a reply. Inother embodiments, the V2V transceiver 110 may emit periodic signalssearching for a reply from an in-range V2V transceiver. If a V2Vtransceiver replies, then a communications link may be established. Anexemplary communication link 203 between the host vehicle 106 and theremote vehicle 108 a is shown in FIG. 2.

As discussed above with FIG. 6, the host vehicle 106 can receive V2Vremote vehicle data 604 from one or more of the remote vehicles 108equipped for V2V communication. Thus, the V2V remote vehicle data 604,as discussed above with FIG. 6, can contains parameters of the remotevehicle 108 that transmitted the V2V remote vehicle data 604. In someembodiments, the V2V remote vehicle data 604 is contained in a messagepacket transmitted from one or more of the remote vehicles 108. Forexample, the message packet can be in a Basic Safety Message (BSM)format as defined for DSRC standards. Vehicles can periodicallybroadcast BSMs to announce their position, velocity, and otherattributes to other vehicles. Information and data received by the hostvehicle 106 can be saved to data logger system 402 and/or the data 310and processed by the C-ACC computer system 302.

Referring again to block 802 of FIG. 8, in one embodiment, receivingremote vehicle data includes receiving remote vehicle data transmittedfrom a leading vehicle positioned ahead of the host vehicle and thepreceding vehicle. For example, in FIGS. 1A and 1B, the host vehicle 106can receive V2V remote vehicle data 604 from the leading vehicle 108 a.In one embodiment, the V2V remote vehicle data 604 includes anacceleration rate of the leading vehicle 108 a.

In another embodiment, receiving remote vehicle data at block 802includes receiving remote vehicle data about remote vehicles and/orobstacles within a proximity of the host vehicle. For example, theremote vehicle data can include an acceleration rate of a precedingvehicle 108 d. In the embodiments discussed herein, the accelerationrate of the preceding vehicle 108 d can be detected by the host vehicle106 using sensors on-board the host vehicle 106, for example, radarsensors. Thus, the remote vehicle data sensed by the host vehicle 106can be sensed remote vehicle data 606. For example, with respect to thehost vehicle 106 and FIG. 6, the host vehicle 106 detects sensed remotevehicle data 606 of the preceding vehicle 108 d using the radar system414. Although the systems and methods discussed herein utilizeacceleration data sensed by radar, it is understood that in otherembodiments, the acceleration data can be received via the vehiclecommunication network 200 if the preceding vehicle 108 d is operablyequipped for V2V communication with the host vehicle 106.

Referring again to FIG. 8, at block 804, the method 800 includesaccessing host vehicle data from the host vehicle. As discussed abovewith FIG. 6, the host vehicle data 602 can be accessed from the vehiclesensor system 322 via the bus 330. In some embodiments, the host vehicledata 602 includes a velocity of the host vehicle 106 and an accelerationrate of the host vehicle 106, however it is understood that the hostvehicle data 602 can include other types of data about the host vehicle106.

At block 806, the method 800 includes calculating an accelerationcontrol rate for the host vehicle. In one embodiment, the accelerationcontrol rate is calculated by the processor 304 according to the C-ACCcontrol model discussed above with equations (1)-(5). Block 806 will nowbe described in greater detail with respect to FIG. 9. FIG. 9illustrates a method 900 for calculating an acceleration control rateaccordingly to an exemplary embodiment. At block 902, the method 900includes determining a relative headway distance between the hostvehicle and the preceding vehicle with respect to a headway referencedistance. For example, as discussed above with equation (1), theprocessor 304 can calculate a distance control component based on arelative distance between the host vehicle 106 and the preceding vehicle108 d and a headway reference distance. The headway reference distanceis a desired separation (e.g., distance) between the host vehicle 106and the preceding vehicle 108 d. The headway reference distance can bepredetermined and stored, for example at the memory 306.

At block 904, the method 900 includes determining a relative velocitybetween a velocity of the host vehicle and a velocity of the precedingvehicle. For example, as discussed above with equation (2), theprocessor 304 can calculate a velocity control component based on avelocity of the host vehicle 106 and a velocity of the preceding vehicle108 d. At block 906, the method 900 includes determining an accelerationrate of the preceding vehicle. For example, as discussed above withblock 802 of FIG. 8, the host vehicle 106 can determine the accelerationrate of the preceding vehicle 108 d using the radar system 414.

At block 908, the method 900 includes calculating an accelerationcontrol rate for the host vehicle to maintain the headway referencedistance between the host vehicle and the preceding vehicle. Inparticular, the acceleration control rate for the host vehicle is basedon the relative headway distance, the relative velocity, theacceleration rate of the preceding vehicle, and the acceleration rate ofthe leading vehicle. Thus, in one embodiment, the processor 304calculates the acceleration control rate for the host vehicle 106according to equation (5) discussed above.

In one embodiment, calculating the acceleration control rate for thehost vehicle can be based on a variable gain associated with theacceleration rate of the leading vehicle. For example, as shown inequations (4) and (5), K_(dsrc) is a leading vehicle accelerationdynamic gain coefficient. Accordingly, at block 910 the method 900 caninclude determining the variable gain. In one embodiment, the variablegain is based on a distance between the host vehicle and the leadingvehicle. In some embodiments, the variable gain is based on a distanceheadway between the host vehicle and the leading vehicle and a timeheadway between the host vehicle and the leading vehicle. The distanceheadway, in some embodiments, is the relative headway distance.

The variable gain can be a function of a distance between the hostvehicle and the leading vehicle. The variable gain can increase as thedistance between the host vehicle and the leading vehicle decreases. Asan illustrative example with reference to FIG. 1B, according to oneembodiment, a variable gain where the remote vehicle 108 a is theleading vehicle would be less than a variable gain where the remotevehicle 108 c is the leading vehicle based on the distance to the hostvehicle 106. In other embodiments, the variable gain can be a functionof a distance headway between the host vehicle and the leading vehicleand/or a time headway between the host vehicle and the leading vehicle.The variable gain can increase as the distance headway and/or the timeheadway increases. The variable gain determined at block 910 can be usedto modify the acceleration rate of the host vehicle by the variable gainat block 912. Further, similar to block 806 of FIG. 8, the accelerationcontrol rate can be calculated at block 908.

Referring back to FIG. 8, the method 800 includes at block 808controlling a vehicle control system of the host vehicle. In oneembodiment, block 808 can include controlling the vehicle control systemof the host vehicle according to the acceleration control rate. Forexample, the acceleration control rate can be output by the C-ACCcontrol system 300 to the ECU 320 in order to control one or morevehicle systems according to the acceleration control rate. For example,the C-ACC control system 300 via the ECU 320 can begin to automaticallydecelerate or accelerate the host vehicle 106 based on the accelerationcontrol rate by controlling the brake actuator 608 and/or the throttleactuator 610. Alternatively or simultaneously, with acceleration and/orbraking of the host vehicle 106, controlling the vehicle control systemof the host vehicle at block 808 can include controlling the vehicleinterface system 328. For example, the C-ACC control system 300 cangenerate information, suggestions, warnings, and/or alerts and providethe same to a driver on display device 510. In other embodiments,tactile feedback can be provided according to the acceleration controlrate. For example, the AFP of the acceleration pedal 514 can providefeedback with active force as the driver pushes the acceleration pedal514 to encourage acceleration and/or deceleration based on theacceleration control rate.

As mentioned above with method 800, the acceleration control rate isbased in part on the acceleration rate of a leading vehicle. Appropriatecontrol of the host vehicle can depend on which remote vehicle isidentified as the leading vehicle. As will now be described withreference to FIG. 10, in some embodiments, the leading vehicle isselected based on the remote vehicle data, specifically, the V2V remotevehicle data 604 transmitted between the host vehicle 106 and one ormore of the remote vehicles 108. FIG. 10 illustrates a method 1000 forselecting a leading vehicle from a plurality of remote vehiclesaccording to an exemplary embodiment. At block 1002, the method 1000includes receiving remote vehicle data from a plurality of remotevehicles. For example, as discussed above with block 802, the hostvehicle 106 is equipped with the V2V transceiver 110 that cancommunicate with other vehicles operable for V2V communication on theroadway 102.

At block 1004, the method 1000 includes selecting the leading vehiclefrom the plurality of remote vehicles by selecting the leading vehiclebased on the remote vehicle data received at block 1002. In oneembodiment, selecting the leading vehicle from the plurality of remotevehicles includes selecting the remote vehicle that has the greatestimpact on the operation of the host vehicle and/or the travel path ofthe host vehicle. The processor 304 can determine which remote vehicleof the plurality of remote vehicles has the greatest impact on the hostvehicle based on the V2V remote vehicle data 604 transmitted from theplurality of remote vehicles 108 and host vehicle data 602 about thehost vehicle 106. For example, determining which remote vehicle 108 hasthe greatest impact on the host vehicle 106 can be based on speed,distance, braking, among others.

In one embodiment, selecting the leading vehicle from the plurality ofremote vehicles includes selecting the leading vehicle from theplurality of remote vehicles that is within a predetermined headway timethreshold from the host vehicle. As an illustrative example with respectto FIG. 1B, the C-ACC control system 300 can set a predetermined headwaytime threshold, stored for example at the memory 306. In one embodiment,the predetermined headway time threshold is five (5) seconds from thehost vehicle 106. Accordingly, in one embodiment, the C-ACC controlsystem 300 selects a leading vehicle from the plurality of remotevehicles in vehicular communication with the host vehicle 106 (e.g., theremote vehicle 108 a, the 108 b, the 108 c) that is within a five secondheadway time threshold from the host vehicle 106. As an illustrativeexample, the remote vehicle 108 c has a three second headway time fromthe host vehicle 106, the remote vehicle 108 b has a five second headwaytime from the host vehicle 106, and the remote vehicle 108 a has a sevensecond headway time from the host vehicle 106. According to thisexample, the leading vehicle would be selected as either the remotevehicle 108 c or the remote vehicle 108 b, which are both within a fivesecond headway time from the host vehicle 106.

In another embodiment, selecting the leading vehicle from the pluralityof remote vehicles includes selecting the leading vehicle from theplurality of remote vehicles based on a deceleration rate of theplurality of remote vehicles. As discussed herein, the plurality ofremote vehicles 108 in vehicular communication with the host vehicle 106can transmit V2V remote vehicle data 604 including speed data, brakingdata, acceleration data, and deceleration data. Thus, in one embodiment,the leading vehicle is selected as the remote vehicle 108 having thegreatest deceleration rate of the plurality of remote vehicles 108.

In another embodiment, selecting the leading vehicle from the pluralityof remote vehicles includes selecting the leading vehicle from theplurality of remote vehicles based on a speed of the plurality of remotevehicles. As discussed herein, the plurality of remote vehicles 108 invehicular communication with the host vehicle 106 can transmit V2Vremote vehicle data 604 including speed data. Thus, in one embodiment,the leading vehicle is selected as the remote vehicle having the lowestspeed of the plurality of remote vehicles. As an illustrative examplewith respect to FIG. 1B, the remote vehicle 108 c has a speed of 35 mph,the remote vehicle 108 b has a speed of 25 mph, and the remote vehicle108 a has a speed of 15 mph. In this example, the remote vehicle 108 awould be selected as the leading vehicle based on having the lowestspeed.

In another embodiment, selecting the leading vehicle from the pluralityof remote vehicles includes selecting the leading vehicle from theplurality of remote vehicles based on a deceleration rate of theplurality of remote vehicles and a speed of the plurality of remotevehicles. In further embodiments, the leading vehicle is the remotevehicle having the lowest speed of the plurality of remote vehicles andthat is within a predetermined headway time threshold from the hostvehicle. In this embodiment and with reference to the examples discussedabove, the remote vehicle 108 b would be selected as the leading vehiclebecause the remote vehicle 108 b is within a predetermined headway timethreshold of five seconds from the host vehicle 106 and has the lowestspeed out of the remote vehicles 108 that are within the predeterminedheadway time threshold.

Upon selecting the leading vehicle, at block 1006, the method 1000includes receiving remote vehicle data from the leading vehicle, forexample, an acceleration rate, as described above with block 802. It isunderstood that the acceleration rate can also be received at block1002. At block 1008, the method 1000 can return to block 802 of method800.

The V2V remote vehicle data 604 received from the leading vehicle iscritical in providing an accurate response by the host vehicle 106. Insome embodiments, the V2V remote vehicle data 604 could be skewed orunavailable due to vehicle communication network 200 issues or issueswith the communication link between the host vehicle 106 and each of theremote vehicles 108. Thus, in some embodiments, selecting a leadingvehicle at block 1004 and/or receiving V2V remote vehicle data 604 fromthe leading vehicle at block 1006 can include methods for monitoringwireless communication connectivity and quality. Referring now to FIG.11, a method 1100 for monitoring communication between the host vehicleand the leading vehicle will be discussed in detail.

At block 1102, the method 1100 includes monitoring a communication linkbetween the host vehicle and the leading vehicle. As discussed abovewith block 802 of FIG. 8, to facilitate communication, a communicationlink is established between the host vehicle 106 and the one or moreremote vehicles 108 operable for V2V communication on the roadway 102.For example, in FIG. 2, the communication link 203 is shown between thehost vehicle 106 and the remote vehicle 108 a. The communication link203 is monitored for packet loss and communication link signal strength.At block 1104, the method 1100 includes determining if a message packethas been lost. DSRC message packets are periodically broadcast to thehost vehicle 106 from the leading vehicle 108 a. In one embodiment,message packets are sent ten times per second. As the host vehicle 106receives the message packets from the leading vehicle 108 a, the hostvehicle 106 can count and store the message packets via the data loggersystem 402 and/or the data 310 and processed by the C-ACC computersystem 302. By tracking the message packets received, the host vehicle106 at block 1104 can identify if a packet has been lost. In someembodiments, the host vehicle 106 can determine a packet loss error rateand compare the packet loss error rate to a predetermine threshold. Inother embodiments, at block 1104, it is determined if the signalstrength of the communication link 203 between the host vehicle 106 andthe leading vehicle 108 a is below a predetermined threshold.

If the determination at block 1104 is YES, the method 1100 proceeds toblock 1106. At block 1106, the remote vehicle data from the messagepacket previously transmitted by the leading vehicle 108 a is utilized,for example, for calculating an acceleration control rate at block 806of FIG. 8. A counter i stored by the memory 306 indicating the number ofpacket losses is also incremented at block 1106.

At block 1108, the counter i is compared to a predetermined threshold N.If the number of lost packets i exceeds the predetermined threshold N,the method 1100 proceeds to block 1110. At block 1110, the method 1100includes selecting a new leading vehicle. For example, in oneembodiment, selecting a new leading vehicle from the plurality of remotevehicles includes selecting the new leading vehicle from the pluralityof remote vehicles that is in closest proximity to the current leadingvehicle. Referring to FIG. 1B, as an illustrative example, the remotevehicle 108 a is the current leading vehicle. Selecting the new leadingvehicle can be based on proximity to the current leading vehicle,namely, the remote vehicle 108 a. Thus, in FIG. 1B, the processor 304can select the remote vehicle 108 b as the new leading vehicle becausethe remote vehicle 108 b is the remote vehicle in closest proximity tothe remote vehicle 108 a. It is understood that in some embodiments,selecting the new leading vehicle can based on other factors (e.g.,deceleration rate, speed) as described above with block 1004 of FIG. 10.

At block 1112, the method 1100 includes monitoring the communicationlink between the host vehicle and the new leading vehicle. Thecommunication link between the host vehicle and the new leading vehicleis monitored for packet loss and signal strength, similar to block 1102.Accordingly at block 1114, it is determined if a message packet has beenlost. In other embodiments, at block 1114 it is determined if the signalstrength of the communication link between the host vehicle and the newleading vehicle is below a predetermined threshold. If the determinationat block 1114 is YES, the method 1100 proceeds to block 1116. At block1116, the processor 304 discards the V2V remote vehicle data 604received from the leading vehicle (e.g., the new leading vehicle) forpurposes of controlling a vehicle control system. For example, theprocessor 304 can calculate the acceleration control rate based only onhost vehicle data 602 and sensed remote vehicle data 606 obtained byon-board sensors (e.g., using the radar system 414). Further, in someembodiments at block 1116, the communication link between the hostvehicle 106 and the new leading vehicle 108 b can be terminated.Controlling the quality of data as described with FIG. 11 mitigates theeffects of skewed or unavailable V2V remote vehicle data 604 on thevehicle control methods described herein.

III. Methods for Hazard Detection

As mentioned above, the systems and methods described herein aregenerally directed to controlling a vehicle using a vehiclecommunication network that can include multiple vehicles andinfrastructures. In some embodiments, systems and methods discussedherein detect hazards that may pose a threat to the operation and/or thetravel path of a host vehicle based in part on vehicular communicationwith one or more of remote vehicles. Thus, the vehicle communicationnetwork 200 and the systems described in FIGS. 2-7 can be used tofacilitate hazard detection and vehicle control using V2V communicationby providing lane level hazard predictions in real-time.

FIG. 12 illustrates an exemplary traffic scenario 1200 that will be usedto describe some of the systems and methods for hazard detectiondiscussed herein. The traffic scenario 1200 is a simplified version ofthe traffic scenario 100 of FIG. 1A. In FIG. 12, the roadway 1202 has afirst lane 1204 a, a second lane 1204 b, and a third lane 1204 c. It isunderstood that the roadway 1202 can have various configurations notshown in FIG. 12, and can have any number of lanes. The roadway 1202includes a host vehicle 1206 and remote vehicles. For simplicity, theremote vehicles will be generally referred to herein as remote vehicles1208. Further, for simplicity, the host vehicle 1206 and the remotevehicles 1208 all include V2V transceivers, although they are notindividually numbered in FIG. 12. It is understood that the host vehicle1206 and the remote vehicles 1208 can have the same or similarcomponents and functions as the host vehicle 106 and the remote vehicles108 discussed above with FIGS. 1A, 1B, 2-7. For example, the hostvehicle 1206 can transmit, receive, and/or exchange communicationsincluding data, messages, images, and/or other information with othervehicles, user, or infrastructures, using DSRC and the vehiclecommunication network 200 of FIG. 2.

By using vehicle information from the remote vehicles 1208 surroundingthe host vehicle 1206 via DSRC, the host vehicle 1206 gains situationalawareness of upcoming hazards and/or can provide better control ofvehicle systems in anticipation of upcoming hazards or lane levelissues. For example, acceleration and deceleration parameters (e.g.,C-ACC computer system 302) can be controlled to smooth braking andeliminate hard braking phantom traffic jams based on upcoming hazards orlane level issues. Accordingly, the dynamics (e.g., motion) of the hostvehicle 1206 and/or an interface of the host vehicle 1206 (e.g., thevehicle interface system 328) can be controlled based, in part, on datafrom DSRC communication with the remote vehicles 1208. Thus, informationpropagated by the remote vehicles 1208 ahead of and/or behind the hostvehicle 1206 provides valuable information to the host vehicle 1206 thatcan increase safety and provide a smoother driving experience. Detailedsystems, methods, and illustrative examples of hazard detection andvehicle control will now be discussed in more detail.

FIG. 13 illustrates a method 1300 for controlling a vehicle controlsystem of a host vehicle using hazard detection. At block 1302, themethod 1300 includes receiving remote vehicle data. For example, asdiscussed above with block 802 of FIG. 8, the host vehicle 1206 isequipped with a V2V transceiver that can communicate with other vehiclesoperable for V2V communication on the roadway 1202. Thus, the hostvehicle 1206 can receive V2V remote vehicle data 604 from remotevehicles 1208 that are equipped for DSRC communication. At block 1304,the method 1300 includes accessing host vehicle data. For example, asdiscussed with block 804 of FIG. 8 and with FIG. 6, the host vehicledata 602 can be accessed from the vehicle sensor system 322 via the bus330. At block 1306, the method 1300 includes detecting a hazard based onthe remote vehicle data and the host vehicle data. In some embodiments,detecting the hazard includes identifying for each remote vehicle 1208 alongitudinal position (e.g., ahead or behind) with respect to the hostvehicle 1206, a lane the remote vehicle 1208 is travelling in withrespect to the host vehicle 1206, and for remote vehicles 1208 not inthe same lane as the host vehicle 1206, a lateral direction (e.g., left,right) with respect to the host vehicle 1206. Accordingly, in oneembodiment, detecting a hazard at block 1306 can include at block 1308,classifying one or more of the remote vehicles 1208 by lane and/orposition relative to the host vehicle 1206. Block 1308 will be discussedin further detail herein with respect to FIGS. 14A and 14B.

In FIG. 13 at block 1310, the method 1300 can optionally includecalculating an acceleration control rate based on the hazard. In oneembodiment, the processor calculates the acceleration control rate forthe host vehicle 1206 according to the control model discussed abovewith respect to equations (1)-(5). For example, in one embodiment,detecting the hazard at block 1306 can include selecting a leadingvehicle as described with block 1004 of FIG. 10 in accordance with thehazard. For example, as will be discussed herein, in one embodiment, aremote vehicle having the greatest deceleration rate and/or the lowest(e.g., slowest) speed in a lane can be identified as a hazard. Thisremote vehicle could be selected as a leading vehicle having thegreatest impact on the operation and/or travel path of the host vehicle1206. Thus, the acceleration rate of this remote vehicle can be used tocalculate the acceleration control rate at block 1310. At block 1312,the method 1300 can include controlling a vehicle control system basedon the hazard and/or according to the acceleration control rate, similarto block 808 of FIG. 8.

As mentioned above, in some embodiments discussed herein, hazarddetection includes identifying for each remote vehicle a longitudinalposition (e.g., ahead or behind) with respect to the host vehicle, alane the remote vehicle is travelling in with respect to the hostvehicle, and for remote vehicles not in the same lane as the hostvehicle, a lateral direction (e.g., left, right) with respect to thehost vehicle. Generally, V2V remote vehicle data 604 received at block1302 of FIG. 12 is parsed and a position of a remote vehicle andprevious positions of the remote vehicle are compared to a position ofthe host vehicle. Methods for classifying the remote vehicles 1208 bylane and position with respect to the host vehicle 1206 will now bediscussed in more detail with reference to FIG. 14A.

FIG. 14A illustrates a method 1400 for classifying remote vehiclesaccording to an exemplary embodiment. In particular, the method 1400provides for lane level classification of remote vehicles relative tothe host vehicle. For each remote vehicle 1208 travelling in the samedirection as the host vehicle 1206 at block 1402, the method 1400proceeds to block 1404, where it is determined if the remote vehicle ispositioned ahead of the host vehicle 1206. More specifically, at block1404, the processor 304 determines a longitudinal position (e.g., aheador behind) with respect to the host vehicle 1206. In one embodiment, theprocessor 304 can use the position data received from the remotevehicles 1208 to determine a longitudinal position. For example, if aremote vehicle azimuth degree is greater than −90 degrees and less than90 degrees, the remote vehicle is determined to be ahead of the hostvehicle 1206. As an illustrative example in FIG. 12, the remote vehicles1208 a-c, 1208 e-f, and 1208 h-j are ahead of the host vehicle 1206,while the remote vehicles 1208 d, 1208 g, and 1208 k are behind the hostvehicle 1206. If the remote vehicle 1208 is ahead of the host vehicle1206, the method 1400 proceeds to block 1406. At block 1406, the method1400 includes calculating and/or predicting a predicted lateral offsetbetween the remote vehicle 1208 and the host vehicle 1206. In someembodiments, block 1406 also includes calculating and/or predicting apredicted longitudinal offset between the remote vehicle 1208 and thehost vehicle 1206.

Block 1406 will now be described in more detail with FIG. 14B, which isa schematic diagram 1412 of a remote vehicle 1414 ahead of a hostvehicle 1416 and travelling in the same direction on a curved roadway1420. The remote vehicle 1414 and the host vehicle 1416 are shown withinan x-axis and y-axis coordinate frame with a reference point (0,VCenterY). In one embodiment, the lateral offset (Predicted LatOffset)and the longitudinal offset (Predicted LongOffset) are predicted using acurrent position of the host vehicle 1416 (HVvehiclePos(0)) and a remotevehicle path trail 1418 of the remote vehicle 1414. The remote vehiclepath trail 1418 is comprised of path history points, which are shown inFIG. 14B as circles along the remote vehicle path trail 1418. The pasthistory points can be remote vehicle data, either received by V2Vcommunication or sensed by the host vehicle 1416, and stored by the hostvehicle 1416.

The remote vehicle path trail 1418 is defined by a line segment thatjoins a current position of the remote vehicle RVPos(0) to consecutivepath history points of the remote vehicle RVPos(−1) to remote RVPos(−N),where N is the total number of path history points. In one embodiment,to calculate the longitudinal offset (Predicted LongOffset), a series oflongitudinal offset points are determined based on individual linesegment distances connecting the current position of the host vehicle1416 vehiclePos(0) to the closest path history points along the remotevehicle path trail 1418 along the y-axis. If the roadway is curved, asshown in FIG. 14B, longitudinal offset (Predicted LongOffset) can bebased on a predicted path 1420 (e.g., arc, radius of the predicted path1420) and a heading of the host vehicle 1416.

To determine a predicted lateral offset (Predicted LatOffset), in oneembodiment, a series of lateral offset points are calculated along theremote vehicle path trail 1418 based on a perpendicular distance betweenthe current position of the host vehicle 1416 and a closest point on theremote vehicle path trail 1418 from the current position of the hostvehicle 1416 along the x-axis. For a curved roadway as shown in FIG.14B, a predicted lateral offset (Predicted LatOffset) can be based on aperpendicular distance between a current position of the remote vehicle1414 (RVPOS(0)) and a projected arc length of the host vehicle 1416.Additional lateral offset points can be based on the arc length of theremote vehicle path trail 1418.

Based on the calculated lateral offset points, a predicted lateraloffset can be determined. For example, in one embodiment, the predictedlateral offset is determined by averaging each lateral offset point. Inanother embodiment, calculating the predicted lateral offset considersweighted factors. More specifically, in one embodiment, calculating thepredicted lateral offset includes calculating the predicted lateraloffset based on one or more perpendicular distances between the currentposition of the host vehicle and one or more path history points of theremote vehicle, and a distance between consecutive path history pointsof the remote vehicle and a current position of the remote vehicle.Referring now to FIG. 14C, a detailed method 1422 for predicting lateraloffset according to an exemplary embodiment is shown. At block 1424,configuration parameters are read, for example, from a look-up tablestored at the data 310. At block 1426, it is determined whetherweighting is enabled based on the configuration parameters from block1424. If weighting is not enabled, the method proceeds to block 1428 andthe predicted lateral offset is calculated using averaging as discussedabove, without weighting. For example, the predicted lateral offset canbe determined by calculating an average of multiple lateral offsetpoints.

If weighting is enabled at block 1426, at block 1430 it is determined ifinverse distance weighting (IDW) is enabled based on the configurationparameters from block 1424. IDW provides more significance to pathhistory points closer in two dimensional Euclidean distance to thecurrent position of the remote vehicle. In one embodiment, the weightvalue can decrease as the distance of the path history points increasefrom the current position of the remote vehicle. If IDW is not enabled,at block 1432, the predicated lateral offset is calculated using anaverage with a default weight factor. For example, the default weightfactor can be expressed mathematically as:

$\begin{matrix}{w_{i} = \frac{1}{i}} & (6)\end{matrix}$

If IDW is enabled, the method 1422 proceeds to block 1434 where the twodimensional Euclidean distance between consecutive path history points(e.g., consecutive path history points on the remote vehicle path trail1418) is calculated according to the following function:

$\begin{matrix}{{di} = {\sqrt{\left( {x_{c} - x_{1}} \right)^{2} + \left( {y_{c} - y_{1}} \right)^{2}} + {\sum\limits_{n = 1}^{i + 1}\sqrt{\left( {x_{n} - x_{n - 1}} \right)^{2} + \left( {y_{n} - y_{n - 1}} \right)^{2}}}}} & (7)\end{matrix}$where x_(c) is a current x-axis position of the remote vehicle, y_(c) isa current y-axis position of the remote vehicles, x₁ is the remotevehicle most recent path history x-axis position (RVPosX(−1)), y₁ is theremote vehicle most recent path history y-axis position (RVPosY(−1)),x_(n) is the remote vehicle n^(th) path history x-axis position, andy_(n) is the remote vehicle n^(th) path history y-axis position. Thetwo-dimensional Euclidean distance considers the distance betweenconsecutive path history points of the remote vehicle 1414 and thecurrent position of the remote vehicle 1414. Referring again to FIG.14C, at block 1436, a weight factor is calculated for the IDW functionbased on the distance between consecutive path history points asdetermined at block 1434. In one embodiment, the weight factor can beexpressed as:

$\begin{matrix}{w_{i} = \frac{1}{d_{i}^{p}}} & (8)\end{matrix}$where p is a power factor used to control weighting memory. Thus, theweight factor in equation (8) is dependent on the distance betweenconsecutive path history points of the remote vehicle 1414 and thecurrent position of the remote vehicle 1414. For example, in oneembodiment, the weight value can decrease as the distance of the pathhistory points increase from the current position of the remote vehicle.Accordingly, at block 1438, the weight factor is applied to calculatethe predicted lateral offset. This can be expressed mathematically as:

$\begin{matrix}{{LatOffsetPredicted} = \frac{{LatOffset}_{1} + {\sum\limits_{k = 3}^{M + 2}{w_{k - 2} \cdot {LatOffset}_{k}}}}{1 + {\sum\limits_{i = 1}^{M}w_{i}}}} & (9)\end{matrix}$

At block 1440, the predicted lateral offset is used to classify the laneand position of the remote vehicle and the process returns to block 1408of FIG. 14A. Referring again to FIG. 14A, at block 1408, the method 1400includes determining and/or assigning a lane to the remote vehicle basedon the predicted lateral offset. The lane is determined and/or assignedrelative to the host vehicle and can include a directional componentwith respect to the host vehicle and/or the host vehicle lane. In oneembodiment, the remote vehicle lane can be determined based on thepredicted lateral offset with respect to the lane widths. Data about thelane widths of the roadway 1202 can be obtained, for example, from mapcomponent data 314. The classification can include a lane identifier(e.g., adjacent lane, same lane), a direction of the lane relative tothe host vehicle and/or the host vehicle lane (e.g., right, left), and adistance associated with the direction of the lane relative to the hostvehicle and/or the host vehicle lane (e.g., far left, far right). Thelane assignments and/or lane classifications of the remote vehicle caninclude, but are not limited to, the same lane as the host vehicle, in aright adjacent lane with respect to the host vehicle, in a right farlane with respect to the host vehicle, in the left adjacent lane withrespect to the host vehicle, and in a left far lane with respect to thehost vehicle. For example, in FIG. 12, the remote vehicle 1208 e is inthe same lane (i.e., the second lane 1204 b) as the host vehicle 1206,the remote vehicle 1208 c is in the left adjacent lane (i.e., the firstlane 1204 a), and the remote vehicle 1208 j is in the right adjacentlane (i.e., the third lane 1204 c). It is understood that other types(e.g., discrete values, numerical values, continuous values) of laneclassifications can be implemented.

At block 1410, the method 1400 includes classifying the remote vehicleat a lane level relative to the host vehicle. This can be based on theremote vehicle lane determined at block 1408. The classification caninclude a lane identifier (e.g., adjacent lane, same lane), a directionof the lane relative to the host vehicle and/or the host vehicle lane(e.g., right, left), and a longitudinal position relative to the hostvehicle (e.g., ahead, behind). For example, a remote vehicle in the samelane as the host vehicle is classified as in the same lane and ahead ofthe host vehicle. A remote vehicle in the left adjacent lane isclassified in the left adjacent lane and ahead of the host vehicle. Aremote vehicle in the right adjacent lane is classified in the rightadjacent lane and ahead of the host vehicle. As an illustrative examplewith respect to FIG. 12, the remote vehicle 1208 c can be classified asin the left adjacent lane 1204 a and ahead of the host vehicle 1206. Itis understood that other types (e.g., discrete values, numerical values,continuous values) of remote vehicle classifications can be implemented.As will be discussed herein, these classifications will be used tofacilitate determination of lane level hazards.

Referring now to FIG. 15 an exemplary method 1500 for hazard detectionusing vehicle communication is shown according to another exemplaryembodiment. In one embodiment, the method 1500 can be used for lanelevel speed hazard detection. Traffic flow condition monitoring helpsavoid unnecessary travel delays and stress to drivers, especially incongested traffic scenarios. Using DSRC communication as describedherein, lane level speed monitoring with V2V remote vehicle data canhelp provide a driver of a host vehicle with lane level traffic flowinformation and/or can be used to control the host vehicle to anticipateand avoid lane level traffic flow issues. FIG. 15 will be described inreference to FIGS. 2-7, 12 and 13. At block 1502, the method 1500includes receiving remote vehicle data as described above with block1302 of FIG. 13. Further, at block 1504, the method 1500 includesaccessing host vehicle data as discussed above with block 1304 of FIG.13. At block 1506, the method 1500 includes classifying the lane andposition of each remote vehicle with respect to the host vehicle asdiscussed above with block 1308 of FIG. 13. At block 1508, the method1500 includes calculating lane level traffic flow data.

In one embodiment, calculating lane level traffic flow data at block1508 can include determining a traffic flow speed for each lane byaveraging the speed of each remote vehicle in each lane ahead of thehost vehicle. As an illustrative example, with respect to FIG. 12, atraffic flow speed for the first lane 1204 a can be determined byaveraging the speed data (e.g., received at block 1502) for remotevehicles 1208 a, 1208 b, and 1208 c, which are in the first lane 1204 aand positioned ahead of the host vehicle 1206. Traffic flow speed forthe lanes 1204 b and 1204 c can similarly be determined.

In another embodiment, calculating lane level traffic flow data at block1508 can include identifying a remote vehicle in each lane having thelowest (e.g., minimum) speed among all remote vehicles in the respectivelane. For example, the processor 304 can determine the speed of eachremote vehicle ahead of the host vehicle 1206 based on the remotevehicle data received at block 1502. For each lane, the processor 304determines which remote vehicle has the lowest speed. As an illustrativeexample, in the first lane 1204 a, the remote vehicle 1208 a may have aspeed of 45 mph, the remote vehicle 1208 b may have a speed of 30 mph,and the remote vehicle 1208 c may have a speed of 35 mph. In thisexample, the processor 304 identifies the remote vehicle 1208 b hashaving the lowest speed in the first lane 1204 a. Remote vehicles withminimum speed for the lanes 1204 b and 1204 c can similarly bedetermined.

In some embodiments the method 1500 can optionally include at block 1510determining if a traffic flow hazard is detected based on the trafficflow data. A traffic flow hazard can affect the operation and/or thetravel path of the host vehicle 1206. For example, in one embodiment, ifa remote vehicle in the same lane as the host vehicle is identified ashaving a minimum speed that is less than a predetermined threshold, theprocessor 304 can determined that a hazard exists. In some embodiments,if the determination at block 1510 is NO, the method can return to block1508. Otherwise, the method 1500 can optionally include at block 1512,calculating an acceleration control rate of the host vehicle. Theacceleration control rate can be based on the traffic flow information.For example, the acceleration control rate can be determined based onthe control model discussed above with equations (1)-(5). In oneembodiment, the leading vehicle can be selected as described at block1004 of FIG. 10 based on the remote vehicle in the same lane as the hostvehicle identified as having the lowest speed and/or the greatestdeceleration rate.

At block 1514, the method 1500 includes controlling a vehicle controlsystem based on the traffic flow data and/or the traffic flow hazard.For example, the processor 304 can generate visual feedback on thedisplay 510 illustrating the traffic flow in each lane and/oridentifying a remote vehicle as a traffic flow hazard. For example, agraphic showing a remote vehicle in the same lane as the host vehicleidentified as having the lowest speed can be highlighted to warn thedriver about the potential traffic flow hazard. It is understood thatother types of feedback based on the traffic flow data can be providedvia the vehicle interface system 328. In other embodiments as describedabove with block 808 of FIG. 8, one or more vehicle systems 404 can becontrolled based on the acceleration control rate and/or the hazard. Forexample, the acceleration control rate can be output by the C-ACCcontrol system 300 to the ECU 320 in order to control one or morevehicle systems according to the acceleration control rate.

Another method for hazard detection using vehicle communication will nowbe described with reference to FIG. 16. Specifically, FIG. 16 shows amethod 1600 for hazard detection based on identifying remote vehiclelane changes according to an exemplary embodiment. FIG. 16 will bedescribed with reference to FIGS. 2-7 and 13. At block 1602, the method1600 includes receiving remote vehicle data as described above withblock 1302 of FIG. 13. Further, at block 1604, the method 1600 includesaccessing host vehicle data as discussed above with block 1304 of FIG.13. At block 1606, the method 1500 includes classifying the lane andposition of each remote vehicle with respect to the host vehicle asdiscussed above with block 1308 of FIG. 13 and with FIGS. 14A, 14B, and14C. In some embodiments, at block 1606, remote vehicles travellingahead of the host vehicle and in the same lane as the host vehicle areidentified (e.g., as classified in FIG. 14A). An illustrative examplewill be described with respect to FIG. 17, which shows a trafficscenario 1700 similar to the traffic scenario 1200 of FIG. 12. Forsimplicity, like numerals represent like elements. In FIG. 17, remotevehicles 1208 c, 1208 d, and 1208 e are travelling ahead of the hostvehicle 1206 in the same lane as the host vehicle 1206.

Referring again to FIG. 16, at block 1608 the method 1600 includesidentifying lane changes of the remote vehicles ahead of the hostvehicle. In one embodiment, the processor 304 analyzes the trajectory(e.g., current position and previous position) of each remote vehicle1208 relative to the host vehicle 1206 trajectory to determine if one ormore of the remote vehicles 1208 have changed lanes within apredetermined time window. The processor 304 can predict ongoing lanechanges by analyzing a turn signal status of each remote vehicle 1208,relative lateral distance between the remote vehicle 1208 and the hostvehicle 1206, lateral acceleration, yaw rate, and heading. In anotherembodiment, for each remote vehicle 1208 travelling ahead of the hostvehicle in the same lane as the host vehicle 1206, it is determined if aturn signal of the remote vehicle 1208 is activated to determine anumber of lane changes.

At block 1610, it is determined if the number of active turn signalsand/or the number of identified lane changes exceeds a predeterminedthreshold. If the determination at block 1610 is NO, a hazard is notdetected and the method 1600 can proceed back to block 1602. Otherwise,at block 1612, it is determined if the speed of the remote vehicles 108is less than a predetermined speed threshold. This decrease in speed canindicate that one or more of the remote vehicles 1208 are slowing downin a similar manner prior to changing lanes. If the determination atblock 1612 is NO, a hazard is not detected and the method 1600 canproceed back to block 1602. Otherwise, at block 1614, the method 1600can optionally include calculating an acceleration control rate. In oneembodiment, the processor 304 calculates the acceleration control ratefor the host vehicle 1206 according to the control model discussed abovewith respect to equations (1)-(5). Further, at block 1616, the method1600 can include controlling a vehicle control system of the hostvehicle based on the lane changes and/or the acceleration control rate.For example, the processor 304 can generate visual feedback on thedisplay 510 illustrating the hazard and/or providing a notificationabout the hazard. For example, the processor 304 can generate a graphicthat illustrates a potential hazard in the same lane as the hostvehicle. The lane and/or hazard can be highlighted to warn the driverabout the potential traffic flow hazard. It is understood that othertypes of feedback based on the traffic flow data can be provided via thevehicle interface system 328. In other embodiments as described abovewith block 808 of FIG. 8, one or more vehicle systems 404 can becontrolled based on the acceleration control rate and/or the hazard. Forexample, the acceleration control rate can be output by the C-ACCcontrol system 300 to the ECU 320 in order to control one or morevehicle systems according to the acceleration control rate.

IV. Methods for Merge Assist

As mentioned above, the systems and methods described herein aregenerally directed to controlling a vehicle using a vehiclecommunication network that can include multiple vehicles andinfrastructures. In some embodiments, cooperative merge assistance canbe provided using a vehicle communication network between vehiclesequipped for V2V (e.g., DSRC) communication. For example, DSRCcommunication can be used to assist a host vehicle merging into a lanewith congested traffic. FIG. 18 illustrates an exemplary trafficscenario 1800 that will be used to describe system and methods forcooperative merge assistance. In FIG. 18, the traffic scenario 1800involves one or more vehicles on a roadway 1802 having a first lane 1804a and a second lane 1804 b. It is understood that the roadway 1802 canhave various configurations not shown in FIG. 18, and can have anynumber of lanes.

The traffic scenario 1800 includes a host vehicle 1806 travelling inlane 1804 b with an intent to merge into lane 1804 a. In someembodiments, the lane 1804 a will be referred to as a merging lane.Remote vehicles are travelling in lane 1804 a. The remote vehicles willbe generally referred to by element number 1808. However, morespecifically, the remote vehicles 1808 can be referred to as a remotevehicle 1808 a, a remote vehicle 1808 b, and a remote vehicle 1808 c. Insome embodiments, the remote vehicles 1808 can be referred to as aplurality of remote vehicles 1808. Similar to the host vehicle 106discussed with FIGS. 1A, 1B, and 2-7, the host vehicle 1806 cantransmit, receive, and/or exchange communications including data,messages, images, and/or other information with other vehicles, user, orinfrastructures, using DSRC. For simplicity, in FIG. 18, the hostvehicle 1806 and the remote vehicles 1808 all include V2V transceivers.It is understood that the host vehicle 1806 and the remote vehicles 1808can include the same or similar components and functions as discussedabove with the host vehicle 106 and the remote vehicles 108. Throughoutthis description of cooperative merge assistance, reference will be madeto the components of FIGS. 2-7.

The host vehicle 1806 can include a plurality of midrange radars orother sensing devices that can be part of the radar system 414. In FIG.18, the plurality of midrange radars may include a front left midrangeradar 1810 located at a front left corner area of the host vehicle 1806,a front right midrange radar 1812 located at a front right corner areaof the host vehicle 1806, a rear left midrange radar 1814 located at arear left corner area of the host vehicle 1806, and a rear rightmidrange radar 1816 located at a rear right corner area of the hostvehicle 1806. However, in other embodiments, the plurality of midrangeradars can be placed in any suitable position on the host vehicle 1806.

Referring now to FIG. 19 a process flow diagram of a method 1900 forproviding cooperative merge assistance using a vehicle communicationnetwork according to an exemplary embodiment is shown. At block 1902,the method 1900 includes activating a merge assist system (e.g., thevehicle computer system 302). For example, user input (e.g., from adriver) can be received from the input portion of the vehicle interfacesystem 328 to activate a merge assist mode. At block 1904, the method1900 includes receiving remote vehicle data about one or more remotevehicles, as discussed above with block 802 of FIG. 8. The remotevehicle data can include V2V remote vehicle data 604 from the remotevehicles 1808 and/or sensed remote vehicle data 606 about the remotevehicles 1808. In one embodiment, the processor 304 can receive speeddata transmitted from the one or more remote vehicles 1808 travelling ina merge lane (e.g., the lane 1804 a) via the vehicle communicationnetwork 200. For example, the processor 304 can receive speed datatransmitted from the one or more remote vehicles 1808 via the vehiclecommunication network 200.

Additionally, in some embodiments, position data of the one or moreremote vehicles 1808 can be received from a sensor system of the hostvehicle 1806 that monitors an area around the host vehicle 1806. Forexample, the processor 304 can receive position data about one or moreof the remote vehicles 1808 via the plurality of midrange sensors (e.g.,sensed remote vehicle data 606 from the radar system 414) as discussedabove with FIG. 18. At block 1906, the method 1900 includes accessinghost vehicle data from the host vehicle. For example, as discussed abovewith block 804 of FIG. 8, the host vehicle data 602 can be accessed fromthe vehicle sensor system 322 via the bus 330.

At block 1908, the method 1900 can optionally include calculating anacceleration control rate. In some embodiments, calculating theacceleration control rate can be calculated with some or all of thecomponents shown in equations (1)-(5) and discussed with block 806 ofFIG. 8. More specifically, the processor 304 calculates the accelerationcontrol rate for the host vehicle 1808 according to the control modeldiscussed above in equations (1)-(5). In one embodiment, which will bediscussed herein, the acceleration control rate of the host vehicle 1806can be based on an average of the speed data received at block 1904. Atblock 1910, the method 1900 can include controlling a vehicle system ofthe host vehicle, similar to block 808 of FIG. 8. For example, in oneembodiment, the processor 304 can control the host vehicle 1806according to the acceleration control rate by providing automaticbraking and/or acceleration for speed control based on the accelerationcontrol rate. In some embodiments, the processor 304 can control thevehicle interface system 328 to provide merge assist feedback to thedriver of the host vehicle 1806. In other embodiments, an active forcepedal (AFP) of the acceleration pedal 514 can be controlled to provideactive feedback force to the driver's foot as the driver pushes theacceleration pedal 514. The method 1900 will now be described in moredetail with reference to FIGS. 20 and 21.

In one embodiment, merge assistance is provided to the host vehicle byproviding speed guidance. The speed guidance assists the host vehicle1806 to a proper speed for merging relative to the remote vehicles 1808.FIG. 20 illustrates a method 2000 for speed guidance using the vehiclecommunication network 200. At block 2002, the method 2000 includesactivating a merge assist system similar to block 1902 of FIG. 19. Atblock 2004, the method 2000 includes receiving V2V remote vehicle data604 via the vehicle communication network 200. More specifically, theprocessor 304 can receive speed data transmitted from the one or moreremote vehicles 1808 travelling in a merge lane (i.e., the lane 1804 a)via the vehicle communication network 200. For example, the processor304 can receive speed data transmitted from the one or more remotevehicles 1808 via the vehicle communication network 200.

At block 2006, the method 2000 can include accessing host vehicle datafrom the host vehicle. For example, as discussed above with block 804 ofFIG. 8, host vehicle data 602 can be accessed from the vehicle sensorsystem 322 of the host vehicle 1806 via the bus 330. In one embodiment,the processor 304 accesses and/or retrieves a speed of the host vehicle1806 and a position of the host vehicle 1806.

At block 2008, the method 2000 includes calculating an average speed ofthe one or more remote vehicles 1808 that are in the merge lane (i.e.,the lane 1804 a). The processor 304 can calculate the average speedbased on the speed data received from each of the remote vehicles 1808via the vehicle communication network 200 at block 2004. Additionally,the processor 304 can compare the average speed to the speed of the hostvehicle 1806 at block 2010. Based on the comparison, at block 2012, themethod 2000 can include calculating an acceleration control rate basedon the average speed and/or the comparison between the average speed tothe host vehicle 1806. The acceleration control rate can be calculatedby the processor 304 to minimize a difference between the average speedof the one or more remote vehicles 1808 and the speed of the hostvehicle 1506.

Said differently, the average speed can be used to calculate and/or seta target acceleration rate of the host vehicle 1806. The processor 304can determine whether the speed of the host vehicle 1806 is above orbelow the target acceleration rate. For example, if the processor 304determines the speed of the host vehicle 1806 is less than the targetacceleration rate, the processor 304 at block 2014 can control a vehiclesystem of the host vehicle 1806 to inform the driver and/orautomatically control the host vehicle 1806 to increase acceleration, asdiscuss herein. For example, the processor 304 can send a command basedon the comparison to the AFP of the acceleration pedal 514 therebyproviding a soft feedback that encourages the driver to provide moreacceleration in order to merge into the lane 1804 a. Alternatively or inaddition, the processor 304 can provide a visual indication to increaseacceleration to the vehicle interface system 328. Further, in someembodiments, at block 2014, the processor 304 can output theacceleration control rate to the vehicle system to control motion of thehost vehicle 1806 according to the acceleration control rate.

If the processor 304 determines that the speed of the host vehicle 1806is greater than the target speed of the host vehicle 1806, the processor304 at block 2014 can send commands to control the AFP of theacceleration pedal 514 to provide active force feedback that simulates apushing force (e.g., pushing back or against) to the foot of the driver.The active force feedback that simulates the pushing force can beprovided with a feedback force that correlates to a difference betweenthe speed of the host vehicle 1806 and the target speed of the hostvehicle 1806. Thus, the driver of the host vehicle 1806 is encouraged toaccelerate and/or decelerate the host vehicle 1806 with a force thatcorrelates to the difference between the speed of the host vehicle 1806and the target speed of the host vehicle 1806. Further, the processor304 can provide a visual indication to decrease and/or increase speed tothe vehicle interface system 328. The brightness of the visualindication can be synchronized with the AFP feedback force that ispositively correlated to the difference in speed.

In addition to providing speed guidance as discussed above with FIG. 20,the systems and methods discussed herein can determine accuratepositioning for merge assistance. Referring now to FIG. 21, a method2100 for merge assistance using position guidance according to anexemplary embodiment is shown. At block 2102, the method 2100 includesactivating a merge assist system similar to block 1902 of FIG. 19. Atblock 2104, the method 2100 includes receiving remote vehicle data. Inone embodiment, the processor 304 can receive V2V remote vehicle data604 (e.g., speed data) as discussed above at block 2004 of FIG. 20.Further, in this embodiment, the processor 304 can receive sensed remotevehicle data 606. More specifically, the processor 304 can receiveposition data about one or more of the remote vehicles 1808 via theplurality of midrange sensors (e.g., sensed remote vehicle data from theradar system 414). Additionally, the method 2100 at block 2106 caninclude accessing host vehicle data 602 as discussed above with block804 of FIG. 8.

At block 2108, it is determined if any objects (e.g., remote vehicles1808, hazards) are detected based on the sensed remote vehicle data 606.More specifically, the processor 304 determines if one or more remotevehicles 1808 are in an area around the host vehicle 1806 based on theposition data. If the determination at block 2108 is NO, the method 2100can proceed to block 2114 to control the vehicle system 404 of the hostvehicle 1806 based on the position data. For example, FIG. 22Aillustrates a traffic scenario 2202 which is a simplified illustrationof the traffic scenario 1800 including the host vehicle 1806. In thisexample, no radar objects (e.g., remote vehicles, hazards) are detectedin the merge lane 1804 a. Accordingly, the processor 304 can control thevehicle interface system 328 to provide a visual indication that it issafe to merge the host vehicle 1806 into the merge lane 1804 a. Forexample, the vehicle interface system 328 can provide a green light onthe display 510. In other embodiments, the processor 304 may control oneor more vehicle systems 404 to assist the driver and/or the host vehicle1806 to merge in to the merge lane 1804 a.

Referring again to FIG. 21, if the determination at block 2108 is YES,the method 2100 can optionally proceed to block 2110 to identify a typeof merge scenario based on a relative position of the host vehicle 1806to the one or more remote vehicles 1808. In one embodiment, the vehiclecomputer system 302 stores merge model data 318. The merge model data318 can be used to identify the type of merge scenario. Thus, control ofthe vehicle systems 404 implemented at block 2114 can be based, in part,on the type of merge scenario. Additionally, in some embodiments, theremote vehicle classification method described in FIGS. 13, 14A, and 14Ccan be used to identify and classify the type of merge scenario. In oneembodiment, the type of merge scenario is one of: a side by side mergescenario as shown in FIG. 22B, a tail merge scenario as shown in FIG.22C, a lead merge scenario as shown in FIG. 22D, or an in-between mergescenario as shown in FIGS. 22E and 22F. Each of these scenarios will bediscussed in more detail herein.

At block 2112, the method 2100 can optionally include calculating anacceleration control rate and/or calculating a safe distance for merginginto the lane based on a relative position of the host vehicle 1206 tothe one or more remote vehicles 1808, a speed of the host vehicle 1806,and a speed of the one or more remote vehicles 1808. In someembodiments, the acceleration control rate and/or the safe distance isalso calculated based on the type of merge scenario determined at block2112. It is understood that in some embodiments, calculating theacceleration control rate can be implemented using equations (1)-(5)discussed above.

With reference to FIG. 22B, a side by side merge scenario 2204 is shown.More specifically, at least one of the remote vehicles, namely, theremote vehicle 1808 a is located adjacent to the host vehicle 1806 inthe merge lane 1804 a. The remote vehicle 1808 a is detected based onthe sensed remote vehicle data 606 received at block 2104. In thisexample, based on the type of merge scenario, at block 2112, theprocessor 304 can calculate an acceleration control rate to slow downthe host vehicle 1806. The processor 304, at block 2114, can control abraking system based on the acceleration control rate by providing adeceleration rate. In one embodiment, the deceleration rate is 0.08 G.Alternatively and/or in addition to the automatic braking control, theprocessor 304 can provide a visual indication to the vehicle interfacesystem 328 to alert and/or encourage an increase in acceleration tomerge. For example, a visual indication can be provided on the display510 to advise the driver of the host vehicle 1806 to slow down byproviding a red colored lighting indication. The red color lightingindication could also indicate to the driver that it is not acceptableto merge into the merge lane 1804 a. Additionally, the processor 304 cancontrol the AFP by providing a large counter feedback force. In oneembodiment, the large counter feedback force may include a 100% counterforce.

Referring again to FIG. 21, as mentioned above, at block 2112, themethod 2100 can also include determining a safe distance for merginginto the merge lane. In one embodiment, the safe distance is a safeboundary for the host vehicle 1806 to merge into the merge lane 1804 abased on one or more remote vehicles 1808 in the merge lane 1804 a. Insome embodiments, the safe distance is based on the type of mergescenario identified at block 2110. With reference to FIG. 22C, a tailmerge scenario 2206 according to an exemplary embodiment is shown. Here,the host vehicle 1806 is positioned adjacent (e.g., in the adjacentlane) to the remote vehicle 1808 a and at the tail end of the remotevehicle 1808 a. In one embodiment, the processor 304 determines the hostvehicle 1806 is positioned to the side (e.g., adjacent) of the remotevehicle 1808 a and at the tail end of the remote vehicle 1808 a and canidentify the type of merge scenario as a tail merge scenario based onthe merge models 318. Based on the type of merge scenario, at block2112, the processor 304 calculates an acceleration control rate to slowdown the host vehicle 1806.

In another embodiment, the processor 304 determines a safe distance forthe host vehicle 1806 to merge into the merge lane 1804 a according tothe following equation:DS=m+1.5s*(V _(HV) −V _(RV))  (10)where m is a constant variable in meters, V_(HV) is a speed of the hostvehicle 1806, and V_(RV) is a speed of the remote vehicle 1808 a. Insome embodiments, the safe distance is limited to a predetermined range,that can be based in part on the merge type. For example, for a tailmerge scenario, between 4 and 25 meters. In one illustrative example,the constant variable m is 5 m. However, in some embodiments, the safedistance equation (10) shown above can be based on the speed of the hostvehicle 1806 and the speed of the remote vehicle 1808 a. For example, ifthe processor 304 determines the speed of the host vehicle 1806 isgreater than the speed of the remote vehicle 1808 a, the constantvariable m can be increased (e.g., from 5 m to 10 m) resulting in alarger safe distance. However, if the speed of the host vehicle 1806 isless than the speed of the remote vehicle 1808 a, the constant variablem can be decreased (e.g., from 5 m to 2 m) resulting in a smaller safedistance.

In one embodiment, the processor 304 determines an actual distance D_(X)between the host vehicle 1806 and the remote vehicle 1808 a as shown inFIG. 22C. The processor 304 can compare the actual distance to the safedistance. If the actual distance is less than the safe distance, thenthe processor 304 determines it is not safe for the host vehicle 1806 tomerge into the lane 1804 a because there is a risk of collision betweenthe host vehicle 1806 and the remote vehicle 1808 a. Accordingly, in oneembodiment, at block 2114, the processor 304 can control the vehicleinterface system 328 to provide feedback to slow down the host vehicle1806. For example, a visual indication can be provided on the display510 indicating it is not safe to merge. Otherwise, if the processor 304determines the actual distance is greater than the safe distance, theprocessor 304 determines it is safe for the host vehicle 1806 to mergeinto the lane 1804 a. The processor 304 can control the vehicleinterface system 328 to provide feedback that it is safe to merge intothe lane 1804 a. For example, the processor 304 can control the display510 to display a green light indicator.

In another embodiment, calculating the safe distance at block 2112 canalso include calculating a control value for controlling a vehiclesystem. For example, upon determining the actual distance between thehost vehicle 1806 and the remote vehicle 1808 a is less than the safedistance, the processor 304 can calculate a control value as a functionof a difference between the actual distance and the safe distance. Inone embodiment, the control value is calculated according to thefollowing equation:

$\begin{matrix}{{CV} = \frac{D_{X} - \left\lbrack {{5m} + {1.5s*\left( {V_{HV} - V_{RV}} \right)}} \right\rbrack}{5m}} & (11)\end{matrix}$The control value can be saturated to a predetermined range. In oneexample, the control value is saturated to a range of −1 to 0. Thecontrol value can be used to control one or more of the vehicle systems404 at block 2114. For example, upon determining the actual distance isless than the safe distance, the processor 304 can calculate anacceleration control rate, based in part on the control value. Asanother example, the processor 304 can control the display 510 toprovide a red colored light with a brightness that can be modifiedand/or adjusted based on the control value. For example, the brightnessof the red colored light can increase as the control value increases.Thus, the closer the host vehicle 1806 is to the remote vehicle 1808 a,the higher the control value and/or the stronger the feedback. Inanother embodiment, the AFP counter force (e.g., feedback force) can beadjusted and/or modified based on the control value. The AFP feedbackforce can increase as the control value increases.

Referring now to FIG. 22D, a lead merge scenario 2208 is shown accordingan exemplary embodiment. Here, the host vehicle 1806 is positioned tothe side (e.g., in the adjacent lane) of the remote vehicle 1808 a andat the front end of the remote vehicle 1808 a. In one embodiment, theprocessor 304 determines the host vehicle 1806 is positioned to the sideof the remote vehicle 1808 a and at the front end of the remote vehicle1808 a, and can identify the type of merge scenario as a lead mergescenario based on the merge model 318. In some embodiments, theprocessor 304 can calculate an acceleration control rate to speed up thehost vehicle 1806 based on the type of merge scenario.

In another embodiment, the processor 304 determines a safe distance forthe host vehicle 1806 to merge into the merge lane 1804 a according tothe following equation:DS=m+1.5s*(V _(HV) −V _(RV))  (12)where m is a constant variable in meters, V_(HV) is a speed of the hostvehicle 1806 and V_(RV) is a speed of the remote vehicle 1808 a. In someembodiments, the safe distance is limited to a predetermined range. Forexample, between 5 and 12 meters. In one illustrative example, theconstant variable m is 8 m. However, in some embodiments, the safedistance equation shown above can be based on the speed of the hostvehicle 1806 and the speed of the remote vehicle 1808 a. For example, ifthe processor 304 determines the speed of the host vehicle 1806 isgreater than the speed of the remote vehicle 1808 a, the constantvariable m can be increased (e.g., from 8 m to 12 m) resulting in alarger safe distance. However, if the speed of the host vehicle 1806 isless than the speed of the remote vehicle 1808 a, the constant variablem can be decreased (e.g., from 8 m to 4 m) resulting in a smaller safedistance.

In one embodiment, the processor 304 determines an actual distance D_(X)between the host vehicle 1806 and the remote vehicle 1808 a as shown inFIG. 22D. The processor 304 can compare the actual distance to the safedistance. If the actual distance is less than the safe distance, thenthe processor 304 determines it is not safe for the host vehicle 1806 tomerge into the lane 1804 a because there is a risk of collision betweenthe host vehicle 1806 and the remote vehicle 1808 a. Accordingly, in oneembodiment, at block 2014, the processor 304 can control the vehicleinterface system 328 to provide feedback to increase the speed of thehost vehicle 1806. For example, a visual indication can be provided onthe display 510 indicating it is not safe to merge. Otherwise, if theprocessor 304 determines the actual distance is greater than the safedistance, the processor 304 determines it is safe for the host vehicle1806 to merge into the lane 1804 a. In this scenario, the processor 304can control the vehicle interface system 328 to provide feedback that itis safe to merge into the lane 1804 a. For example, the processor 304can control the display 510 to display a green light indicator.

In another embodiment, calculating the safe distance at block 2112 canalso include calculating a control value for controlling the vehiclesystem. For example, upon determining the actual distance between thehost vehicle 1806 and the remote vehicle 1808 a is less than the safedistance, the processor 304 can calculate a control value as a functionof a difference between the actual distance and the safe distance. Inone embodiment, the control value is calculated according to thefollowing equation:

$\begin{matrix}{{CV} = \frac{D_{X} - \left\lbrack {{8m} + {1.5s*\left( {V_{HV} - V_{RV}} \right)}} \right\rbrack}{{8m} + {1.5s*\left( {V_{HV} - V_{RV}} \right)}}} & (13)\end{matrix}$

The control value can be saturated according to a predetermined range.For example, in one embodiment, the control value is saturated to arange of −1 to 0. The control value can be used to control one or morevehicle systems 404 at block 2114. For example, upon determining theactual distance is less than the safe distance, the processor 304 cancalculate an acceleration control rate, based in part on the controlvalue. As another example, the processor 304 can control the display 510to provide a blue colored light with a brightness that can be modifiedand/or adjusted based on the control value. For example, the brightnessof the blue colored light can increase as the control value increases.Thus, the closer the host vehicle 1806 is to the remote vehicle 1808 a,the higher the control value and the stronger the feedback.

With reference to FIGS. 22E and 22F, an in-between merge scenario 2210and 2212 according to an exemplary embodiment is shown. In FIG. 22E, thehost vehicle 1806 is positioned is positioned adjacent (e.g., in theadjacent lane) to the remote vehicles 1808 a and 1808 b and in-betweenthe remote vehicles 1808 a and 1808 b. In this embodiment, at block2112, the processor 304 calculates a safe distance based on a front safedistance from the host vehicle 1806 to the remote vehicle 1808 a and arear safe distance from the host vehicle 1806 to the remote vehicle 1808b. More specifically, the front safe distance is calculated according tothe following equations:Front_(DS) =m+1.5s*(V _(HV) −V _(RVF))  (14)where m is a constant variable in meters, V_(HV) is a speed of the hostvehicle 1806 and V_(RVF) is a speed of the front remote vehicle 1808 a.In some embodiments, the safe distance is limited to a predeterminedrange, that can be based in part, on the merge type. For example, for anin-between scenario as shown in FIG. 22E, the safe distance can belimited between 4 and 20 meters. In one embodiment, the processor 304determines an actual front distance D_(FX) between the host vehicle 1806and the front remote vehicle 1808 a. The processor 304 can compare theactual front distance to the front safe distance. If the actual frontdistance is less than the safe front distance, then the processor 304determines it is not safe for the host vehicle 1806 to merge into thelane 1804 a because there is a risk of collision between the hostvehicle 1806 and the front remote vehicle 1808 a. Accordingly, in oneembodiment, at block 2114, the processor 304 can control the vehicleinterface system 328 to provide feedback to slow down the host vehicle1806. For example, a visual indication can be provided on the display510 indicating it is not safe to merge.

In another embodiment, calculating the safe distance at block 2112 canalso include calculating a control value for controlling the vehiclesystem. For example, upon determining the actual front distance betweenthe host vehicle 1806 and the front remote vehicle 1808 a is less thanthe safe front distance, the processor 304 can calculate a control valueas a function of a difference between the actual front distance and thesafe front distance. In one embodiment, the control value is calculatedaccording to the following equation:

$\begin{matrix}{{Front}_{CV} = \frac{D_{FX} - \left\lbrack {{5m} + {1.5s*\left( {V_{HV} - V_{RVF}} \right)}} \right\rbrack}{5m}} & (15)\end{matrix}$The control value can be saturated to a predetermined range. In oneexample, the control value is saturated to a range of −1 to 0. Thecontrol value can be used to control one or more vehicle systems 404 atblock 2114. For example, upon determining the actual front distance isless than the safe distance, the processor 304 can calculate anacceleration control rate, based in part on the control value. Asanother example, the processor 304 can control the display 510 toprovide a red colored light with a brightness that can be modifiedand/or adjusted based on the control value. For example, the brightnessof the red colored light can increase as the control value increases.Thus, the closer the host vehicle 1806 is to the front remote vehicle1808 a, the higher the control value and the stronger the feedback. Inanother embodiment, the AFP counter force (e.g., feedback force) can beadjusted and/or modified based on the control value. The AFP feedbackforce can increase as the control value increases.

With reference to in-between merge scenario 2212 of FIG. 22F, the hostvehicle 1806 is closer to the rear remote vehicle 1808 b than the frontremote vehicle 1808 a. This is in contrast to the in-between mergescenario 2210 of FIG. 22E where the host vehicle 1806 was closer to thefront remote vehicle 1808 a than the rear remote vehicle 1808 b. In theembodiment of FIG. 22F, at block 2112, the processor 304 calculates asafe distance based on a rear safe distance from the host vehicle 1806to the rear vehicle 1808 b. More specifically, the rear safe distance iscalculated according to the following equations:Rear_(DS) =m+1.5s*(V _(HV) −V _(RVR))  (16)where m is a constant variable in meters, is a speed of the host vehicle1806 and V_(RVR) is a speed of the rear remote vehicle 1808 b. In someembodiments, the safe distance is limited to a predetermined range, thatcan be based in part, on the merge type. For example, for an in-betweenscenario as shown in FIG. 22F, the safe distance can be limited between5 and 8 meters. In one embodiment, the processor 304 determines anactual rear distance D_(RX) between the host vehicle 1806 and the rearremote vehicle 1808 b as shown in FIG. 22F. The processor 304 cancompare the actual rear distance to the rear safe distance. If theactual rear distance is less than the safe rear distance, then theprocessor 304 determines it is not safe for the host vehicle 1806 tomerge into the lane 1804 a because there is a risk of collision betweenthe host vehicle 1806 and the rear remote vehicle 1808 b. Accordingly,in one embodiment, at block 2114, the processor 304 can control thevehicle interface system 328 to provide feedback to increase the speedof the host vehicle 1806. For example, a visual indication can beprovided on the display 510 indicating it is not safe to merge.

In another embodiment, calculating the safe distance at block 2112 canalso include calculating a rear control value for controlling thevehicle system. For example, upon determining the actual rear distancebetween the host vehicle 1806 and the rear remote vehicle 1808 a is lessthan the rear safe distance, the processor 304 can calculate a controlvalue as a function of a difference between the actual rear distance andthe safe rear distance. In one embodiment, the control value iscalculated according to the following equation:

$\begin{matrix}{{Rear}_{CV} = \frac{D_{X} - \left\lbrack {{8m} + {1.5s*\left( {V_{HV} - V_{RV}} \right)}} \right\rbrack}{{8m} + {1.5s*\left( {V_{HV} - V_{RV}} \right)}}} & (17)\end{matrix}$The control value can be saturated to a predetermined range. In oneexample, the control value is saturated to a range of −1 to 0. Thecontrol value can be used to control one or more vehicle systems 404 atblock 2114. For example, upon determining the actual rear distance isless than the rear safe distance, the processor 304 can calculate anacceleration control rate, based in part on the control value. Asanother example, the processor 304 can control the display 510 toprovide a blue colored light with a brightness that can be modifiedand/or adjusted based on the control value. For example, the brightnessof the blue colored light can increase as the control value increases.Thus, the closer the host vehicle 1806 is to the rear remote vehicle1808 b, the higher the control value and the stronger the feedback.

Based on the equations above, if the processor 304 determines that theactual rear distance is greater than the rear safe distance and theactual front rear distance is greater than the front safe distance, theprocessor 304 determines that it is safe for the host vehicle 1806 tomerge into the lane 1804 a. The processor 304 can control the vehicleinterface system 328 to provide feedback that it is safe to merge intothe lane 1804 a. For example, the processor 304 can control the display510 to display a green light indicator.

V. Methods for Vehicle Control in Tailgating Scenarios

The systems and methods discussed above can also be applied to atailgating scenario. During a tailgating scenario, a following vehicleis driving closely behind a host vehicle such that the distance (e.g.,headway distance) between the two vehicles does not guarantee that acollision can be avoided when either vehicle stops. At highway speeds,it is recommended that the headway distance between a host vehicle and afollowing vehicle be maintained by a distance, measured in time, of atleast two seconds. A distance of less than two seconds can be consideredtailgating, and tailgating can increase the likelihood of rear endcollisions. Tailgating also creates other challenges for the hostvehicle. For example, a driver of the host vehicle can become nervous inthe presence of a tailgating vehicle since the likelihood of collisioncan increase during sudden braking of the host vehicle. Systems andmethods for handling tailgating vehicles, which can be implemented inpart or in whole with the systems and methods discussed above, will nowbe discussed.

FIG. 23A illustrates an exemplary traffic scenario 2300 that will beused to describe some of the systems and methods for vehicle control intailgating scenarios. The traffic scenario 2300 is a simplified versionof the traffic scenario 100 of FIG. 1A. For simplicity, like numeralsrepresent like elements. In FIG. 23A, the roadway 2302 has a first lane2304 a, a second lane 2304 b, and a third lane 2304 c. It is understoodthat the roadway 2302 can have various configurations not shown in FIG.23A, and can have any number of lanes. The traffic scenario 2300includes a host vehicle 2306 and remote vehicles. For simplicity, theremote vehicles will be generally referred to herein as remote vehicles2308.

It is understood that the host vehicle 2306 and the remote vehicles 2308can have the same or similar components and functions as the hostvehicle 106 and the remote vehicles 108 discussed above with FIGS. 1A,1B, 2-7. For example, the host vehicle 2306 can transmit, receive,and/or exchange communications including data, messages, images, and/orother information with other vehicles, user, or infrastructures, usingDSRC via a vehicle-to-vehicle (V2V) transceiver 2310 and the vehiclecommunication network 200 of FIG. 2. Further, the remote vehicle 2308 a,the remote vehicle 2308 b, and the remote vehicle 2308 d, can use itsrespective V2V transceiver to communicate with one another and the hostvehicle 2306. Although not shown in FIG. 23A, in some embodiments, theremote vehicle 2308 c and the remote vehicle 2308 e can also includeequipment for communication using the vehicle communication network 200.

Referring now to FIG. 23B, a schematic view is shown of the host vehicle2306 and the remote vehicles 2308 travelling in the second lane 2304 bof FIG. 23A. More specifically, as show from left to right, the remotevehicle 2308 a, the remote vehicle 2308 b, the host vehicle 2306, andthe remote vehicle 2308 d. As mentioned above, the components shown inFIG. 23B can have the same or similar components and functions as thehost vehicle 106 and the remote vehicles 108 discussed above with FIGS.1A and 1B. In this embodiment, and in the exemplary tailgating systemsand methods discussed herein, the remote vehicle 2308 a can be referredto as a leading vehicle, the remote vehicle 2308 b can be referred to asa preceding vehicle, and the remote vehicle 2308 d can be referred to asa rear vehicle or a following vehicle. In some embodiments, thepreceding vehicle can be referred to as a first vehicle and the rearvehicle or the following vehicle can be referred to as a second vehicle.The rear vehicle 2308 d is a remote vehicle driving behind the hostvehicle 2306 in the same lane (i.e., the second lane 2304 b) as the hostvehicle 2306. In some embodiments, the rear vehicle 2308 d can beidentified and referred to as a tailgating vehicle. As will be discussedherein in more detail, a tailgating vehicle can be identified based on acomparison of a distance and/or a time headway distance between the hostvehicle 2306 and the rear vehicle 2308 d to a predetermined threshold.Further, the tailgating vehicle can be identified as a hazard withrespect to the embodiments discussed above in Section III.

Generally, the embodiments discussed herein include control of vehiclessystems based, in part, on information regarding a rear vehicle drivingbehind a host vehicle and in the same lane as the host vehicle. In someembodiments, control of one or more of the vehicle systems is performedbased on the rear vehicle, the host vehicle, a preceding vehicle and/ora leading vehicle. In particular, the methods and systems discussedherein provide braking control and/or Cooperative Adaptive CruiseControl (C-ACC). In some embodiments, these methods and systems canutilize the vehicle communication network 200 shown in FIG. 2.

The host vehicle 2306 will now be described in more detail withreference to FIG. 24. FIG. 24 is a block diagram of an exemplary controlsystem 2400 of the host vehicle 2306 for use with tailgating scenarios.In particular, FIG. 24 is a simplified diagram of the control system 300of FIG. 3, but includes detailed components of a braking system that areoriginally shown in FIGS. 5 and 6. For simplicity, like numerals inFIGS. 3 and 24 represent like elements. Further, it is understood thatthe control system 2400 can include other components not shown and/ordiscussed in detail above with FIG. 3.

The components associated functions shown in FIG. 24 can be implementedwith other vehicles. For example, the remote vehicles 2308 can includeone or more of the components and functionalities of the control system2400. Further, in some embodiments, the control system 2400 will bereferred to as a braking control system and/or a C-ACC control system.Other braking systems and/or C-ACC systems associated with some vehiclesmay include different elements and/or arrangements as configured to thecontrol system 2400, but can be configured to communicate over thevehicle communication network 200 with one or more other brakingsystems, C-ACC systems, vehicle control systems, or merge assistsystems.

In FIG. 24, the control system 2400 includes a vehicle computer system2402. In some embodiments discussed herein, the vehicle computer system2402 will be referred to as a braking computer system 2402 and/or aC-ACC computer system 2402. In other embodiments, the vehicle computersystem 2402 can be associated with another type of vehicle controlsystem or can be a general vehicle computing device that facilitates thefunctions described herein. As discussed above in detail with FIG. 3,the control system 2400 includes a processor 2404, a memory 2406,instructions 2408, and data 2410. The vehicle computer system 2402 cancommunicate with various components of the host vehicle 2306 using, forexample, a bus 2430. As discussed above in detail with FIG. 3, thevehicle computer system 2402 can communicate with the vehicle electroniccontrol unit (ECU) 2420, a vehicle sensor system 2422, a vehiclecommunication system 2424, a vehicle navigation system 2426, and avehicle interface system 2428.

As discussed with FIGS. 5 and 6, acceleration and/or decelerationcommands (e.g., according to an acceleration control rate) can beexecuted using, in part, a brake actuator and/or a throttle actuator. Asshown in FIG. 24, the control system 2400 includes a brake actuator 2432operatively connected to a brake pedal 2434. The control system 2400also includes a throttle actuator 2436 operatively connected to anacceleration pedal 2438. The brake actuator 2432 controls deceleration(vehicle speed decreases) by controlling, for example, brake fluidpressure via a master cylinder, fluid pressure control values, and brakewheel cylinders (not shown). The deceleration can also be controlled bydriver input received by stepping on the brake pedal 2434, in which thebrake actuator 2432 produces brake fluid pressure, which is transmittedto the brake wheel cylinders.

In contrast, the throttle actuator 2436 controls acceleration (vehiclespeed increases) by varying the opening of a throttle valve (not shown).The acceleration can be controlled, in part, by driver input received bystepping on the acceleration pedal 2438. The brake actuator 2432, thebrake pedal 2434, the throttle actuator 2436, and the acceleration pedal2438 can include various sensors which are represented in FIG. 24 by thevehicle sensor system 2422. In some embodiments, these components can bepart of a brake assist system or any other type of braking controlsystem Sensors associated with the brake actuator 2432, the brake pedal2434, the throttle actuator 2436, and the acceleration pedal 2438 caninclude, but are not limited to, acceleration sensors, wheel speedsensors, brake fluid pressure sensors, brake pedal travel sensors, brakepedal force sensors, and brake pedal application sensors. As will bediscussed herein in more detail, the control system 2400 controls thebrake actuator 2432 (e.g., braking force) and the throttle actuator 2436(e.g., opening of the throttle valve), for example, based on anacceleration control rate, to bring the host vehicle 2306 to a speedcloser to the acceleration control rate generated by the C-ACC computersystem 2402.

Referring now to FIG. 25, an exemplary control model 2500 for brakingcontrol and/or C-ACC control for tailgating scenarios is shown. FIG. 25is similar to the C-ACC control model of FIG. 6, but includes specificbrake components. In particular, FIG. 25 includes the brake pedal 2434and the acceleration pedal 2438. For simplicity, like numerals in FIG. 6and FIG. 25 represent like elements. As discussed above in detail withFIG. 6, the control model 2500 receives as inputs host vehicle data2502, V2V remote vehicle data 2504, and sensed remote vehicle data 2506.The host vehicle data 2502 includes vehicle dynamics data about the hostvehicle 106. For example, speed, acceleration, velocity, yaw rate,steering angle, throttle angle, range or distance data, among others.The host vehicle data 2502 can be accessed from the vehicle sensorsystem 2422 via the bus 2430. Further, as shown in FIG. 25, the brakepedal 2434 and/or the acceleration pedal 2438 can be sources of hostvehicle data 2502. The host vehicle data 2502 can be provided viasensors discussed above (e.g., vehicle sensor system 2422) associatedwith the brake actuator 2432, the throttle actuator 2436, the brakepedal 2434 and/or the acceleration pedal 2438. In some embodiments, hostvehicle data 2502 provided by sensors associated with the brake actuator2432, the throttle actuator 2436, the brake pedal 2434 and/or theacceleration pedal 2438, can be referred to herein as host vehiclebraking data.

As discussed in detail with FIG. 6, the V2V remote vehicle data 2504includes remote vehicle dynamics data about one or more of the remotevehicles 2308 communicated via the vehicle communication network 200.The V2V remote vehicle data 2504 can include speed, acceleration,velocity, yaw rate, steering angle, and throttle angle, range ordistance data, among others, about one or more of the remote vehicles2308. In some embodiments, V2V remote vehicle data 2504 associated witha braking operation of a remote vehicle can be referred to herein as V2Vremote vehicle braking data. As discussed above, the sensed remotevehicle data 2506 can include data about one or more of the remotevehicles 2308 and/or other objects in proximity to the host vehicle2306, received and/or sensed by the vehicle sensor system 2422. In someembodiments, sensed remote vehicle data 2506 associated with a brakingoperation of a remote vehicle can be referred to herein as sensed remotevehicle braking data.

The host vehicle data 2502, the V2V remote vehicle data 2504, and thesensed remote vehicle data 2506 can be input to the computer system2402, is processed using the control algorithms with tailgatingscenarios discussed herein. In one embodiment, the computer system 2402can output acceleration and/or deceleration commands to the ECU 2420,which then executes said commands to the respective vehicle system, forexample, the brake actuator 2432 and/or the throttle actuator 2436.

A. Methods for Brake Boost Control

Generally, some drivers find it challenging to apply hard-braking (e.g.,emergency braking, panic braking) in an emergency situation, forexample, when a preceding vehicle suddenly decelerates. It can be evenmore challenging to provide hard-braking in the presence of a tailgatingvehicle. Drivers may be hesitant to brake when they are aware atailgating vehicle is present because braking could potentially lead toa rear-end collision with the tailgating vehicle. Accordingly, brakeassistance can be provided based on a panic brake operation, a precedingvehicle and/or a tailgating vehicle. In some embodiments, V2Vcommunication of this brake assistance can be provided to other vehiclesto further mitigate risk of collision. In the systems and methodsdiscussed herein, a tailgating vehicle (e.g., a tailgater) includes avehicle following a subject vehicle (e.g., a host vehicle) and separatedby a distance and/or a time headway that is sufficiently small towarrant further analysis for various reasons. For example, as discussedherein, a brake boost operation can be applied to a subject vehicle toreduce the likelihood of the following vehicle (e.g., a tailgater) rearending the subject vehicle.

Referring now to FIG. 26A an exemplary method 2600 for braking controlwith tailgating scenarios will be described with reference to FIGS. 23A,23B, 24, and 25. The method 2600 includes, at block 2602, detecting,using one or more vehicle sensors, a panic brake operation. In otherembodiments, the panic brake operation can be referred to as ahard-brake operation or an emergency brake operation. The processor 2404can use host vehicle braking data (e.g., host vehicle data 2502)captured via the vehicle sensor system 2422 to determine if a panicbrake operation is occurring. In one embodiment, the processor 2404 candetect a panic brake operation based on a change of a braking pressureof the vehicle control system 2400 of the host vehicle 2306 with respectto time. The processor 2404 can calculate the change of the breakingpressure and compare the change of the braking pressure to a panic brakepressure threshold. In another embodiment, the processor 2404 canmonitor a change of a braking pressure of the braking system withrespect to time.

At block 2604, the method 2600 includes, detecting, using the one ormore vehicle sensors, a rear vehicle in the same lane as the hostvehicle, but behind the host vehicle (e.g., generally longitudinallyaligned, or aligned in the same direction of travel). For example, theprocessor 2404 can detect the rear vehicle 2308 d driving behind thehost vehicle 2306 and in the same lane as the host vehicle 2306 based onsensed remote vehicle data 2506. In one embodiment, the processor 2404can receive position data about one or more of the remote vehicles 2308via a plurality of midrange sensors (e.g., sensed remote vehicle data2506 from the radar system 414). With respect to the illustrativeexample in FIG. 23B, the rear vehicle 2308 d can be detected as a secondvehicle (e.g., a rear vehicle, a following vehicle) driving behind thehost vehicle 2306 and in the same lane (i.e., 2304 b) as the hostvehicle 2306. In one embodiment, which will be discussed in detail withFIG. 27, block 2604 can also include determining if the rear vehicle2308 d is a tailgating vehicle.

At block 2606, the method 2600 includes, determining, using the one ormore vehicle sensors, a time-to-collision value between the host vehicleand the rear vehicle. The time-to-collision value represents an amountof time before a collision between the host vehicle 2306 and the rearvehicle 2308 d will occur. In one embodiment, the time-to-collisionvalue is based only a driver braking pressure provided by operation ofthe brake pedal 2434 (e.g., deceleration rate determined at block 2608).Thus, the time-to-collision threshold can be an amount of time before acollision between the host vehicle 2306 and the rear vehicle 2308 d willoccur based on an amount of deceleration provided by only the driver viainput to the brake pedal 2434. In some embodiments, the processor 2404can calculate a time-to-collision value between the host vehicle 2306and the rear vehicle 2308 d based on a speed of the host vehicle 2306, aspeed of the rear vehicle 2308 d, and/or a distance or time headwaybetween the host vehicle 2306 and the rear vehicle 2308 d.

At block 2608, the method 2600 includes, determining, using the one ormore vehicle sensors, a deceleration rate of the host vehicle. Thedeceleration rate can be based on a driver braking pressure provided byoperation of the brake pedal 2434 of the braking system. Thus, thedeceleration rate is an amount of deceleration provided by only thedriver via input to the brake pedal 2434. For example, the processor2404 can calculate the deceleration rate of the host vehicle 2306 basedon host vehicle braking data received from a brake pedal travel sensorand/or a brake pedal force sensor.

Further, at block 2610, the method 2600 includes, controlling thebraking system based on the time-to-collision value and the decelerationrate. In one embodiment, controlling the braking system includesincreasing the braking pressure of the vehicle control system 2400 to anamount greater than the driver braking pressure based on thetime-to-collision value and the deceleration rate. Thus, the processor2404 can control the vehicle control system 2400 (e.g., the brakingsystem) by generating a braking signal that increases the brakingpressure of the braking system to an amount greater than brakingpressure provided by the driver only. This operation can be referred toas a brake boost operation, which increases a force the brake pedal 2434exerts on the brake master cylinder by using, for example, engine vacuumand pressure.

In another embodiment, a brake boost operation may not be applied atblock 2610 (e.g., the brake boost operation is suppressed). Instead,only braking provided according to the driver braking pressure isexecuted. According to this embodiment, when the time-to-collision valueis less than a time-to-collision threshold or the deceleration rate isgreater than a deceleration rate threshold, controlling the vehiclecontrol system 2400 at block 2610, includes braking the host vehicle2306 only according to the driver braking pressure. In anotherembodiment, which will be described in detail with FIG. 27, when thetime-to-collision value is less than a time-to-collision threshold orthe deceleration rate is greater than a deceleration rate threshold,controlling the braking system at block 2610 includes not executing abrake boost operation (e.g., suppressing the brake boost operation).

In one embodiment, controlling the vehicle control system 2400 at block2610 also includes using V2V communication via the vehicle communicationnetwork 200. For example, if a brake boost operation is executed byincreasing the braking pressure, the host vehicle 2306 can communicateinformation about the brake boost operation (e.g., deceleration rate,warning, alert) to the rear vehicle 2308 d using the vehicularcommunication network 200 (e.g., via DSRC messages). In otherembodiments, the vehicle control system 2400 can control one or morevehicle systems to provide one or more notifications to the tailgatingvehicle, for example, visual indicators or brake light indications thatcan be perceived as a warning to a driver of the tailgating vehicle.

The method 2600 of FIG. 26 will now be described in greater detail withthe method 2700 of FIG. 27. At block 2702, similar to block 2602 of themethod 2600, the method 2700 includes, detecting, using one or morevehicle sensors, a panic brake operation. As an illustrative examplewith reference to FIG. 28, a graph 2800 displays exemplary brakingpressure over time for a strong brake pressure 2802, a weak brakepressure 2804, and a boosted brake pressure 2806. At point 2808, a panicbrake operation is detected as shown by a sharp rise over a small amountof time in the braking pressure. Thus, in this embodiment, the processor2404 can calculate the change of the breaking pressure and compare thechange of the braking pressure to a panic brake pressure threshold.Alternatively, the processor 2404 can monitor a change of a brakingpressure of the braking system with respect to time.

If the determination at block 2702 is YES, the method 2700 proceeds toblock 2704, otherwise, the method 2700 ends. At block 2704, the method2700 includes determining whether a tailgating vehicle is present withrespect to the host vehicle. In particular, it is determined whether therear vehicle 2308 d is a tailgating vehicle. This determination can bebased on one or more factors, for example, a distance between the hostvehicle 2306 and the rear vehicle 2308 d and/or a speed threshold. Asused herein, a headway distance can be defined as a distance between afirst vehicle and a second vehicle in front of the first vehicle. Insome embodiments a headway distance can include a temporal component asa time headway distance, defined as a measurement of the time past a setpoint between a first and second vehicle. The headway distance and timeheadway distance calculations can include preset times and/or distancesbased on one or more factors, for example, road conditions, speed,weather conditions, among others.

Thus, in one embodiment, it is determined whether the rear vehicle 2308d is a tailgating vehicle based on comparing a distance between the hostvehicle 2306 and the rear vehicle 2308 d to a tailgating distancethreshold (e.g., 100 meters). In another embodiment, a rear headwaydistance between the host vehicle 2306 and the rear vehicle 2308 d iscompared to a tailgating headway distance threshold (e.g., 0.5-2seconds). In some embodiments, block 2702 can include determining if therear headway distance is within a predetermined range (e.g., tolerancevalue) of the tailgating headway distance threshold. For example, if therear headway distance between within 1 second (+/−1) of the tailgatingheadway distance threshold.

Methods described above with block 2604 in FIG. 26 for detecting a rearvehicle can also be used to determine whether the rear vehicle is atailgating vehicle. For example, the processor 2404 can receive positiondata about the second vehicle via a plurality of midrange sensors (e.g.,sensed remote vehicle data 2506 from the radar system 414). From theposition data, the processor 2404 can compare a distance between thehost vehicle 2306 and the rear vehicle 2308 d to a tailgating headwaydistance threshold. In other embodiments, from the position data, theprocessor 2404 can determine a rear headway distance of the rear vehicle2308 d with respect to the host vehicle 2306, and compare the rearheadway distance to a tailgating headway distance threshold. Withreference to the illustrative example of FIG. 23B, it is determinedwhether the rear vehicle 2308 d is a tailgating vehicle based on thedistance D_(R), which is a distance between the front of the rearvehicle 2308 d and the tail end of the host vehicle 2306.

If the determination at block 2704 is YES, the method 2700 proceeds toblock 2706, otherwise the method 2700 proceeds to block 2710. At block2706, similar to block 2606 of the method 2600, the method 2700includes, determining, using the one or more vehicle sensors, atime-to-collision value between the host vehicle and the second vehicle.At block 2708, the time-to-collision value is compared to atime-to-collision threshold. More specifically, it is determined if thetime-to-collision value is less than the time-to-collision threshold.The time-to-collision threshold can be an amount of time that triggers acollision warning or actuates control of one or more vehicle systems tomitigate collision. In one embodiment, the time-to-collision thresholdis about 1-2 seconds. If the determination at block 2708 is YES, themethod 2700 ends. Thus, in one embodiment, when the time-to-collisionvalue is less than the time-to-collision threshold (e.g., 1-2 seconds),the vehicle control system 2400 is controlled to not execute a brakeboost operation (e.g., suppress the brake boost operation). Since thetime-to-collision value does not meet the critical threshold (e.g., thetime-to-collision threshold), the vehicle control system 2400 does notassist braking control and the only braking provided is that from thedriver via driver input at the brake pedal 2434.

If the determination at block 2708 is NO, the method 2700 proceeds toblock 2710. Thus, in this embodiment, if a tailgating vehicle is notpresent at block 2704 or the time-to-collision value is greater than thetime-to-collision threshold, the method 2700 proceeds to block 2710. Atblock 2710, the method 2700 includes determining a deceleration rate,similar to block 2608 of method 2600. More specifically, thedeceleration rate can be based on a driver braking pressure provided byoperation of the brake pedal 2434. Further, at block 2712, the method2700 includes comparing the deceleration rate to a deceleration ratethreshold. Specifically, it is determined whether the deceleration rateis less than the deceleration rate threshold. In some embodiments, thedeceleration rate threshold is about 0.1 g-0.8 g. For example, in someembodiments, the deceleration rate threshold is 0.5 g. In otherembodiments, at block 2712, it can be determined if the decelerationrate is within a predetermine range (e.g., tolerance value) of thedeceleration rate threshold. For example, if the deceleration rate iswithin 0.2 g (+/−0.2 g) of the deceleration rate threshold. In someembodiments, the deceleration rate threshold is referred to as a maxdeceleration rate.

If the determination at block 2712 is NO, the method 2700 ends. Thus, inone embodiment, if the deceleration rate is greater than thedeceleration rate threshold (e.g., 0.5 g), the vehicle control system2400 is controlled to not execute a brake boost operation (e.g.,suppress the brake boost operation). Accordingly, the vehicle controlsystem 2400 does not assist braking control and only provides brakingbased on driver input at the brake pedal 2434. This can be due to thefact that the driver input alone is providing a sufficient brakingpressure. For example, with reference to FIG. 28, at point 2810, thebraking pressure for the strong brake pressure 2802 is greater than 0.5g, and the braking pressure for the weak brake pressure 2804 is lessthan 0.5 g.

However, if the determination at block 2712 is YES, the method 2700proceeds to block 2714 where controlling the vehicle control system 2400(e.g., the braking system) includes executing a brake boost operation.For example, when the time-to-collision value is greater than thetime-to-collision threshold at block 2708 (NO), and the decelerationrate is less than the deceleration rate threshold at block 2712 (YES),controlling the vehicle control system 2400 at block 2714 includesexecuting a brake boost operation by increasing the braking pressure ofthe braking system to an amount greater than the driver braking pressure(i.e., greater than the braking provided by driver input at the brakepedal 2434 only). As shown in FIG. 28, the weak brake pressure 2804 canbe boosted according to the boosted brake pressure 2806 to increase thebraking pressure to an amount similar to the strong brake pressure 2802.Thus, the boosted brake pressure 2806 is exemplary braking pressureafter the panic brake operation is detected and the brake boostoperation is executed.

In another embodiment, when the time-to-collision value is greater thanthe time-to-collision threshold at block 2708 (NO), and the decelerationrate is less than the deceleration rate threshold at block 2712 (YES),controlling the braking system at block 2714 includes executing a brakeboost operation by increasing the braking pressure of the braking systemto an amount greater than the driver braking pressure to therebyincrease the deceleration rate to a maximum deceleration rate. In someembodiments, the maximum deceleration rate is about 0.1 g-0.8 g. Forexample, in one embodiments, the maximum deceleration rate is 0.5 g.Accordingly, a potential rear-end collision can be mitigated using brakeassistance following the panic brake operation and in view of apreceding vehicle and/or a tailgating vehicle.

Additionally, as discussed above with FIG. 26, in some embodimentscontrolling the braking system at block 2714 also includes using V2Vcommunication via the vehicle communication network 200. For example, ifa brake boost operation is executed by increasing the braking pressure,the host vehicle 2306 can communicate information about the brake boostoperation (e.g., deceleration rate, warning, alert) to the rear vehicle2308 d using the vehicular communication network 200 (e.g., via DSRCmessages). In other embodiments, visual notifications can be provided,for example, visual indicators or brake light indications that can beperceived as a warning to a driver of the tailgating vehicle.Accordingly, brake assistance and communication of brake assistance canbe applied to the host vehicle 2306 to reduce the likelihood of the rearvehicle 2308 d rear ending the host vehicle 2306.

B. Methods for C-ACC Tailgate Control

In addition to or in lieu of brake boost operation, the systems andmethods described herein can provided C-ACC control with tailgatingscenarios. As discussed in detail in Section I above, motion of the hostvehicle 2306 can be controlled, for example, by the C-ACC control system2400. In particular, the C-ACC control system 2400 can controllongitudinal motion of the host vehicle 2306. For example, the C-ACCcontrol system 2400 can control acceleration and/or deceleration of thehost vehicle 2306 in relation to the preceding vehicle 2308 b bygenerating an acceleration control rate using the C-ACC control modelequations (1)-(5). However, in some embodiments, controlling the motionof the host vehicle 2306 can consider the rear vehicle 2308 d, which canbe a tailgating vehicle. Thus, the C-ACC control system 2400 candynamically adjust deceleration of the host vehicle 2306 to mitigaterisk of tailgater related accidents.

As discussed in detail above with equations (1) and (2), a controlalgorithm for C-ACC control can include a distance control componentbased on the relative distance between the host vehicle 2306 and thepreceding vehicle 2308 b and a preceding headway reference distance. Thecontrol algorithm can also include a velocity control component shown inequation (3) based on the relative velocity between the host vehicle2306 and the preceding vehicle 2308 b. Thus, the distance and velocitycomponents of the control algorithm maintain a predetermined precedingheadway reference distance between the host vehicle 2306 and thepreceding vehicle 2308 b. If a preceding vehicle is not present, thedistance and velocity components of the control algorithm can be set topredetermined values (e.g., desired values input by a driver).

In the embodiments discussed herein, if the rear vehicle 2308 d, whichcan be a tailgating vehicle, is present, the acceleration control ratebased on the preceding vehicle 2308 b can be determined and/or modifiedbased on the rear vehicle 2308 d. More specifically, the accelerationcontrol rate can be determined and/or modified based on a predeterminedrear headway reference distance. Accordingly, in one embodiment, anacceleration control reference is based on and/or can be modifiedaccording to a rear headway distance component, which can be expressedmathematically as:a _(ref) _(rear) =K _(rear)(x _(i) −x _(i+1) −h{dot over (x)} _(i+1) −L_(RV))  (18)where x_(i+1) is a distance from a rear end of the rear vehicle 2308 dto the front end of the host vehicle 2306, x_(i) is a length of the hostvehicle 2306, h{dot over (x)}_(i+1) is a predetermined rear headwayreference distance and L_(RV) is the length of the rear vehicle 2308 d.These variables are schematically shown in FIG. 2366. It is understoodthat information about the rear vehicle 2308 d (e.g., distance,velocity) is sensed remote vehicle data 2506 (e.g., radar data detectedusing radar sensors), but it is understood that in other embodiments theinformation about the rear vehicle 2308 d can be V2V remote vehicle data2504 received by the host vehicle 2306 using DSRC via the vehiclecommunication network 200. Further, in other embodiments, theinformation about the rear vehicle 2308 d can be V2V remote vehicle data2504 received by the host vehicle 2306 from roadside equipment (RSE)116. Thus, in some embodiments, the acceleration control rate can bedetermined and/or modified based on the distance control component andthe velocity control component of equation (3) and the rear vehiclecomponent as shown in equation (18), which can be expressedmathematically as:a _(ref) =K _(p)(x _(i−1) −x _(i) −h{dot over (x)} _(i) −L _(PV))+K_(v)(v _(i−1) −v _(i))+K _(rear)(x _(i) −x _(i+1) −h{dot over (x)}_(i+1) −L _(RV))  (19)where x_(i−1) is a distance from a rear end of the host vehicle 2306 tothe front end of the preceding vehicle 2308 b, x_(i) is a length of thehost vehicle 2306, h{dot over (x)}_(i) is a pre-determined headwayreference distance and L_(PV) is the length of the preceding vehicle2308 b, and where is a velocity of the preceding vehicle 2308 b, v_(i)is the velocity of the host vehicle 2306. Thus, an acceleration controlrate can be generated and/or modified by the C-ACC computer system 302based on a relative headway distance between the host vehicle 2306 andthe preceding vehicle 2308 b with respect to a headway referencedistance, a relative velocity between a velocity of the host vehicle2306 and a velocity of the preceding vehicle 2308 b, and a relative rearheadway distance between the host vehicle 2306 and the rear vehicle 2308d with respect to a rear headway reference distance. It is understoodthat, in some embodiments, the information about the preceding vehicle2308 b (e.g., distance, velocity) is sensed remote vehicle data 2506(e.g., radar data detected using radar sensors), but it is understoodthat in other embodiments the information about the preceding vehicle2308 b can be V2V remote vehicle data 2504 received by the host vehicle2306 using DSRC via the vehicle communication network 200. Further, inother embodiments, the information about the preceding vehicle 2308 bcan be V2V remote vehicle data 2504 received by the host vehicle 2306from roadside equipment (RSE) 116.

It is appreciated that in some embodiments, the acceleration controlreference of equation (7) can also consider information about theleading vehicle 2308 a. For example, the acceleration control rate canbe modified and/or generated based on an acceleration rate of theleading vehicle 2308 a and/or a leading vehicle acceleration dynamicgain coefficient. Thus, the acceleration control rate can be generatedand/or modified by the C-ACC computer system 302 using the distancecomponent, the velocity component, the rear vehicle component of therear vehicle 2308 d, and an acceleration component of the leadingvehicle 2308 a. This can be expressed mathematically as,a _(ref) =K _(p)(x _(i−1) −x _(i) −L _(PV))+K _(v)(v _(i−1) −v _(i))+K_(rear)(x _(i) −x _(i+1) −h{dot over (x)} _(i+1) −L _(RV))+K _(a) −a_(L)  (20)where a_(L) is an acceleration rate of the leading vehicle 2308 a andK_(a) is a leading vehicle acceleration dynamic gain coefficient. Insome embodiments, similar to those described in Section I(C) and SectionII above, the acceleration rate of the leading vehicle 2308 a isreceived by the host vehicle 2306 from the leading vehicle 2308 a usingDSRC via the vehicle communication network 200. However, it isunderstood that in other embodiments, the acceleration rate of theleading vehicle 2308 a can be received by the host vehicle 2306 from RSE116 and/or other remote vehicles.

Referring now to FIG. 29, an exemplary method 2900 for controlling ahost vehicle based on a preceding vehicle and a tailgating vehicle willnow be described according to an exemplary embodiment and with referenceto the control algorithm of equations (18)-(20). FIG. 29 will also bedescribed with reference to FIGS. 23A, 23B, 24, and 25. In theembodiment shown in FIG. 29, a vehicle control system will be referredto as a C-ACC control system 2400. Further, it is understood that one ormore of the components of FIG. 29 can be implemented with one or more ofthe components of FIGS. 8-10 discussed above in detail in Section II.Additionally, one or more of the components of FIG. 29 can be can becombined, omitted or organized with other components or organized intodifferent architectures.

Referring now to method 2900, at block 2902, the method 2900 includes,detecting, using the one or more vehicle sensors, a rear vehicle drivingbehind the host vehicle and in the same lane as the host vehicle. Forexample, the vehicle computer system 2402 can detect whether a rearvehicle is driving behind the host vehicle 2306 and in the same lane asthe host vehicle 2306 based on sensed remote vehicle data 2506. Withrespect to the illustrative example shown in FIGS. 23A and 23B, the rearvehicle 2308 d can be detected as driving behind the host vehicle 2306and in the same lane (i.e., the second lane 2304 b) as the host vehicle2306. As will be described in detail below, the rear vehicle 2308 d canbe a tailgating vehicle and longitudinal motion of the host vehicle 2306can be adjusted dynamically based on the preceding vehicle 2308 b and/orthe rear vehicle 2308 d.

In some embodiments, the determination at block 2902 can be based, inpart, on V2V remote vehicle data 2504. In one embodiment, the processor2404 can receive position data about one or more of the remote vehicles2308 via a plurality of midrange sensors (e.g., sensed remote vehicledata 2506 from the radar system 414). In one embodiment, which will bediscussed in detail with FIG. 30, block 2904 can also includedetermining if the rear vehicle 2308 d is a tailgating vehicle.

At block 2904, the method 2900 includes detecting, using one or morevehicle sensors, a braking operation. More specifically, the brakingoperation is initiated by the vehicle system of the host vehicle. Theprocessor 2404 can detect a braking operation by monitoring host vehiclebraking data (e.g., host vehicle data 2502) from the vehicle sensorsystem 2422. Based on the braking data, the processor 2404 can determineif a braking operation is being initiated and executed by, for example,the C-ACC control system 2400. This braking operation is in contrast toa braking operation initiated by, for example, a driver via driver inputat the brake pedal 2434.

More specifically, in this embodiment, the braking operation detected atblock 2902 causes the host vehicle 2306 to decelerate (vehicle speeddecreases) based on an acceleration control rate generated by the C-ACCcontrol system 2400 in order to maintain a preceding headway referencedistance with the preceding vehicle 2308 b. Thus, the braking operationdetected at block 2902 is initiated at the host vehicle 2306 in responseto the preceding vehicle 2308 b to thereby increase the precedingheadway distance between the host vehicle 2306 and the preceding vehicle2308 b. Thus, the acceleration control rate is calculated to achieveand/or maintain a preceding headway distance between the host vehicle2306 and the preceding vehicle 2308 b. Accordingly, the accelerationcontrol rate generated by the C-ACC control system 2400 that initiatesthe braking operation detected at block 2902 is calculated withoutconsideration of the rear vehicle 2308 d. For example, if the precedingvehicle 2308 b decelerates (e.g., the relative distance between the hostvehicle 2306 and the preceding vehicle 2308 b decreases with respect tothe predetermined preceding headway reference distance), the C-ACCcontrol system 2400 generates an acceleration control rate (e.g., basedon the control algorithm shown in equation (5)) that brings the hostvehicle 2306 to a speed closer to the preceding vehicle 2308 b. Thus,the acceleration control rate can be based on the preceding vehicle 2308b using the distance component, the velocity component, and theacceleration component of the preceding vehicle 2308 b. In someembodiments, the acceleration control rate can also be based on theacceleration component of the leading vehicle 2308 a, as described abovein Section I(C) and equations (1)-(5).

Thus, in this embodiment, the acceleration control rate will cause thehost vehicle to decelerate at a particular rate and this deceleration isinitiated by the host vehicle 2306 (e.g., via the C-ACC control system2400). Said differently, the braking operation causes the host vehicle2306 to decelerate based on an acceleration control rate generated bythe C-ACC control system 2400 in order to maintain a preceding headwayreference distance with the first vehicle 2308 b. As an illustrativeexample, the acceleration control rate may be −0.5 m/s based on thepreceding vehicle 2308 b as discussed above. The current accelerationrate of the host vehicle 2306 may be 1.5 m/s, thus, the accelerationcontrol rate executed at the host vehicle 2306 will cause the currentacceleration control rate to decrease by 0.5 m/s to 1.0 m/s. Thisnegative acceleration or decrease in the current acceleration controlrate is achieved by controlling the host vehicle 2306 (e.g., the brakingsystem) according to the acceleration control rate, for example, byinitiating a braking operation at the host vehicle 2306.

In other embodiments, detecting and/or determining the braking operationat block 2904 includes receiving from the vehicle system of the hostvehicle an acceleration control rate that when executed by the hostvehicle initiates a braking operation by the vehicle system of the hostvehicle. Thus, in this embodiment, the processor 2404 can receive anacceleration control rate generated by the C-ACC control system 2400. Asdiscussed above, the acceleration control rate can be generated by theC-ACC control system 2400 to maintain a preceding headway referencedistance with the first vehicle.

In some embodiments which will be discussed in further detail herein,the braking operation detected is a hard-braking operation (e.g., panicbrake operation, emergency brake operation). Thus, in one embodiment,block 2904 can include determining whether the braking operation is ahard-braking operation. For example, the acceleration control rate canbe compared to a predetermined braking threshold. As an illustrativeexample, braking that meets or exceeds 1 m/s can be considered ahard-braking operation.

At block 2906, the method 2900 includes, determining, using the one ormore vehicle sensors, a relative rear headway distance between the hostvehicle and the rear vehicle with respect to a rear headway referencedistance. For example, as discussed above with equation (18), theprocessor 2404 can calculate a distance control component based on arelative distance between the host vehicle 206 and the rear vehicle 2308d and a rear headway reference distance. The rear headway referencedistance is a desired separation (e.g., distance, time headway) betweenthe host vehicle 2306 and the rear vehicle 2308 d. The rear headwayreference distance can be predetermined and stored, for example at thememory 2406. In some embodiments, the rear headway reference distance isset by the driver (e.g., via driver input).

At block 2908, the method 2900 includes, modifying the accelerationcontrol rate based on the relative rear headway distance and the rearheadway reference distance. Thus, the acceleration control rate based onthe preceding vehicle 2308 b is modified to consider the rear vehicle2308 d. For example, as discussed above with equation (19), theprocessor 2404 can determine and/or modify the acceleration control rateas a function of the acceleration of the host vehicle 2306, thepreceding vehicle 2308 b, and the rear vehicle 2308 d.

At block 2910, the method 2900 includes controlling the host vehicle2306 based on the modified acceleration control rate. For example, inone embodiment, the processor 2404 can control the braking operation ofthe vehicle system to decelerate the host vehicle according to themodified acceleration control rate. As will be discussed in more detailherein with FIG. 31, the braking operation can be controlled bygradually decelerating the host vehicle 2306 according to the modifiedacceleration control rate. By modifying deceleration of the host vehicle2306 by applying a smaller brake initially and then gradually applyingbraking to reach the modified acceleration control rate, more reactiontime is given to the rear vehicle 2308 d. Said differently, theacceleration control rate and thus the preceding headway referencedistance can be modified so that the preceding headway referencedistance gradually increases.

The method 2900 will now be discussed in more detail with reference tothe method 3000 of FIG. 30. At block 3002, the method 3000 includesdetermining whether a tailgating vehicle is present with respect to thehost vehicle. This determination can be based on one or more factors,for example, a distance between the host vehicle 2306 and the rearvehicle 2308 d and/or a speed threshold. As used herein, a headwaydistance can be defined as a distance between a first vehicle and asecond vehicle in front of the first vehicle. In some embodiments aheadway distance can include a temporal component as a time headwaydistance, defined as a measurement of the time past a set point betweena first and second vehicle. The headway distance and time headwaydistance calculations can include preset times and/or distances based onone or more factors, for example, road conditions, speed, weatherconditions, among others.

Thus, in one embodiment, it is determined whether the rear vehicle 2308d is a tailgating vehicle based on comparing a distance between the hostvehicle 2306 and the rear vehicle 2308 d to a tailgating distancethreshold (e.g., 100 meters). In another embodiment, a rear headwaydistance between the host vehicle 2306 and the rear vehicle 2308 d iscompared to a tailgating headway distance threshold (e.g., 0.5-2seconds). In some embodiments, block 3002 can include determining if therear headway distance is within a predetermined range (e.g., tolerancevalue) of the tailgating headway distance threshold. For example, if therear headway distance between within 1 second (+/−1) of the tailgatingheadway distance threshold. Methods described above with block 2904 fordetecting a rear vehicle can also be used to determine whether the rearvehicle 2308 d is a tailgating vehicle.

If the determination at block 3002 is NO, the method 3000 the C-ACCcontrol system 2400 controls motion of the host vehicle 2306 accordingto the acceleration control rate at block 3004, which is generated bythe C-ACC control system 2400 in order to maintain a preceding headwayreference distance with the preceding vehicle 2308 b. Thus, the hostvehicle 2306 is controlled according to the acceleration control ratewithout consideration of the rear vehicle 2308 d (e.g., according to thecontrol algorithm of equation (5)). Thus, in some embodiments,controlling the host vehicle 2306 based on the rear vehicle 2308 d isonly executed if the rear vehicle 2308 d is a tailgating vehicle becausethe risk of rear-end collision with the host vehicle 2306 is higher ifbraking at the host vehicle 2306 is induced by the preceding vehicle2308 b.

In some embodiments, if the determination at block 3002 is YES, themethod 3000 can optionally include at block 3006, determining whetherthe rear vehicle 2308 d is tailgating the host vehicle 2306 for apredetermined period of time. Said differently, it is determined if therear vehicle 2308 d is within the tailgating distance threshold for apredetermined of time. This confirms that the rear vehicle 2308 d is atailgating vehicle and is consistently within a distance and/or headwaydistance that is sufficiently small to be considered tailgating. Thus, atemporal component is considered at block 3006 that quantifies how longthe rear vehicle 2308 d maintains a distance and/or headway distance tothe host vehicle 2306 that is sufficiently small to be consideredtailgating.

In other embodiments, block 3006 can include determining how manyinstances of tailgating the rear vehicle 2308 d engages in with the hostvehicle 2306 within a predetermined period of time. For example, if therear vehicle 2308 d comes within a distance of less than a two secondheadway distance to the host vehicle 2306, then increases the distanceto more than a two second headway distance to the host vehicle 2306, andthen decreases to a distance less than a two second headway distance tothe host vehicle 2306, the rear vehicle 2308 d is considered atailgating vehicle at two different time intervals and/or instances. Ifthese two different instances occur within a predetermined amount oftime (e.g., two minutes), the rear vehicle 2308 d is confirmed as atailgating vehicle with respect to the host vehicle 2306.

If the determination at block 3006 is YES, the method 3000 canoptionally proceed to block 3008, where the preceding headway referencedistance, which is used to calculate the acceleration control rate bythe C-ACC control system 2400, is modified to increase the followingdistance between the host vehicle 2306 and the preceding vehicle 2308 b.Thus, in one embodiment, the preceding headway reference distance isincreased at block 3008. Accordingly at block 3010, the processor 2404and/or the C-ACC control system 2400 can modify the acceleration controlrate to increase the following distance between the host vehicle 2306and the preceding vehicle 2308 b, and at block 3020, the C-ACC controlsystem 2400 can control the host vehicle 2306 according to the modifiedacceleration control rate. Preemptively increasing the followingdistance between the host vehicle 2306 and the preceding vehicle 2308 bafter detection of a tailgating vehicle can provide additional time tothe tailgating vehicle to react. Additionally, by preemptivelyincreasing the following distance, the C-ACC control system 2400 canapply less braking force if heard-braking occurs by the precedingvehicle 2308 b and/or the leading vehicle 2308 a.

It is understood that in some embodiments, modifying the precedingheadway reference distance and controlling the host vehicle 2306accordingly can include the C-ACC control system 2400 modifying and/oroverriding preset C-ACC gap times and/or levels. Thus, upon detection ofa tailgating vehicle as discussed with block 3002 and 3006, the C-ACCcontrol system 2400 can change and/or override a C-ACC gap time toincrease the C-ACC gap time between the host vehicle 2306 and thepreceding vehicle 2308 b.

Returning to the method 3000 of FIG. 30, at block 3012, similar to block2902 of the method 2900, the method 3000 includes, detecting, using oneor more vehicle sensors, a braking operation initiated by the hostvehicle 2306. In some embodiments, the braking operation detected is ahard-braking operation (e.g., panic brake operation, emergency brakeoperation). Thus, in one embodiment, block 2904 can include determiningwhether the braking operation is a hard-braking operation. For example,the acceleration control rate can be compared to a predetermined brakingthreshold. As an illustrative example, braking that meets or exceeds 1m/s can be considered a hard-braking operation. If the determination atblock 3012 is YES, the method 3000 proceeds to block 3014, otherwise,the method proceeds to block 3004.

In some embodiments, even if a tailgating vehicle is detected,maintaining a safe following distance between the host vehicle 2306 andthe preceding vehicle 2308 b is given preference over the followingdistance between the tailgating vehicle and the host vehicle 2306. Forexample, if the distance between the host vehicle 2306 and the precedingvehicle 2308 b decreases very abruptly, which causes a high decelerationrate at the host vehicle 2306, deference is given to maintaining thepreceding a headway distance between the host vehicle 2306 and thepreceding vehicle 2308 b. Thus, at block 3014, the method 3000 caninclude comparing the acceleration control rate to a braking ratethreshold. Here, it is determined whether the deceleration of the hostvehicle 2306 meets a threshold. In some embodiments, this can beconsidered an extremely hard-braking operation. As an illustrativeexample, a deceleration rate that meets or exceeds 1.5 m/s can beconsidered an extremely hard-braking operation. In this instance,information about the rear vehicle 2308 d can be ignored since thepreceding vehicle 2308 b is given priority. If the determination atblock 3014 is YES, the method 3000 proceeds to block 3004, otherwise,the method proceeds to block 3016.

Thus, upon determining the acceleration control rate meets the brakingrate threshold, controlling the braking operation of the host vehicle2306 includes decelerating the host vehicle according to theacceleration control rate and the preceding vehicle 2308 b (e.g.,according to the control algorithm in equation (5)). Otherwise, themethod 3000 proceeds to block 3016 to determine a rear vehicle componentas described above with block 2906. Thus, at block 3018, the method 3000includes modifying the acceleration control rate based on the relativerear headway distance and the rear headway reference distance. Here, theacceleration control rate based on the preceding vehicle 2308 b ismodified to consider the rear vehicle 2308 d. For example, as discussedabove with equation (19), the processor 2404 can determine and/or modifythe acceleration control rate as a function of the acceleration of thehost vehicle 2306, the preceding vehicle 2308 b, and the rear vehicle2308 d.

At block 3020, the method 3000 includes controlling the host vehiclebased on the modified acceleration control rate. For example, the C-ACCcontrol system 2400 can execute control of the host vehicle 2306according to the modified acceleration control rate. In one embodiment,block 3020 includes controlling deceleration of the host vehicle 2306.For example, controlling the braking operation of the host vehicle 2306can include gradually decelerating the host vehicle 2306 according tothe acceleration control rate, the preceding vehicle 2308 b, and therear vehicle 2308 d. Accordingly, gradual deceleration that achieves apreceding headway distance and a rear headway distance can provide morereaction time for a tailgating vehicle. Controlling the brakingoperation in this manner will now be described with reference to themethod 3100 of FIG. 31.

At block 3102, the method 3100 includes determining an initialacceleration control rate that is less than the modified accelerationcontrol rate based on the relative rear headway distance and the rearheadway reference distance. In this embodiment, controlling the brakingoperation includes gradually increasing deceleration of the host vehicle2306 from the initial acceleration control rate to the modifiedacceleration control rate based on the relative rear headway distanceand the rear headway reference distance. By modifying deceleration ofthe host vehicle 2306 by applying a smaller brake initially and thengradually applying braking to reach the modified acceleration controlrate, more reaction time is given to the rear vehicle 2308 d. Saiddifferently, the acceleration control rate is modified thereby modifyingthe preceding headway reference distance based on the relative rearheadway distance and the rear headway reference distance. The gradualdeceleration of the vehicle thereby gradually increases the precedingheadway reference distance.

Thus, at block 3104, the C-ACC control system 2400 can execute controlof the host vehicle 2306 according to the initial acceleration controlrate. At block 3106, the method 3100 can include detect and/ormonitoring a trigger event to initiate a gradual increase indeceleration towards the modified acceleration control rate. Forexample, in one embodiment, the initial acceleration rate is maintainedfor a period of time until a braking operation is detected at the rearvehicle 2308 d. Said differently, an initial preceding headway referencedistance (i.e., less than the preceding headway reference distanceachieved by the modified acceleration control rate) is maintained for aperiod of time.

The processor 2404 can receive position data about the rear vehicle 2308d via a plurality of midrange sensors (e.g., sensed remote vehicle data2506) or can receive braking and/or position information from the rearvehicle 2308 d using V2V communication (e.g., V2V remote vehicle data2504). The processor 2404 can detect a braking operation at the rearvehicle 2308 d using this position data. Thus, at block 3108, the method3100 can include gradually increasing deceleration of the host vehiclefrom the initial acceleration control rate to the modified accelerationcontrol rate based on the relative rear headway distance and the rearheadway reference distance. According to this embodiment, a smallerbrake is applied initially for a period of time, until the host vehicle2306 determines that the rear vehicle 2308 d has reacted to the initialdeceleration of the host vehicle 2306 by applying a braking operation inresponse. Said differently, braking is applied so to gradually increasethe initial preceding headway reference distance to the precedingheadway reference distance achieved by the modified acceleration controlrate.

It is understood that the embodiments disclosed in Section V withrespect to tailgating scenarios can also be implemented in whole or inpart with the methods discussed in Sections II-IV. For example, withrespect to hazard detection, a tailgating vehicle can be considered ahazard, and vehicle control using V2V communication by providing lanelevel hazard predictions in real-time can be implemented as discussedabove in Section III. Additionally, the tailgating control model can beused for merge assist, particularly in a lead merge scenario (FIG. 22d )and in-between scenarios (FIGS. 22E and 22F), where a remote vehicle isdetected as a tailgating vehicle.

The embodiments discussed herein can also be described and implementedin the context of computer-readable storage medium storing computerexecutable instructions. Computer-readable storage media includescomputer storage media and communication media. For example, flashmemory drives, digital versatile discs (DVDs), compact discs (CDs),floppy disks, and tape cassettes. Computer-readable storage media caninclude volatile and nonvolatile, removable and non-removable mediaimplemented in any method or technology for storage of information suchas computer readable instructions, data structures, modules or otherdata. Computer-readable storage media excludes non-transitory tangiblemedia and propagated data signals.

It will be appreciated that various implementations of theabove-disclosed and other features and functions, or alternatives orvarieties thereof, can be desirably combined into many other differentsystems or applications. Also that various presently unforeseen orunanticipated alternatives, modifications, variations or improvementstherein can be subsequently made by those skilled in the art which arealso intended to be encompassed herein.

The invention claimed is:
 1. A computer-implemented method forcontrolling a vehicle system that controls motion of a host vehiclerelative to a first vehicle positioned immediately ahead of the hostvehicle, comprising: detecting, using one or more vehicle sensors, asecond vehicle driving behind the host vehicle and in the same lane asthe host vehicle; detecting, using the one or more vehicle sensors, abraking operation initiated by the vehicle system of the host vehicle,wherein the braking operation causes the host vehicle to deceleratebased on an acceleration control rate generated by the vehicle system inorder to maintain a preceding headway reference distance with the firstvehicle, and detecting the braking operation includes comparing theacceleration control rate to a braking rate threshold; determining,using the one or more vehicle sensors, a relative rear headway distancebetween the host vehicle and the second vehicle with respect to a rearheadway reference distance; determining a modified acceleration controlrate based on the relative rear headway distance and the rear headwayreference distance, and an initial acceleration control rate based onthe relative rear headway distance and the rear headway referencedistance, wherein the initial acceleration control rate is less than themodified acceleration control rate; controlling the braking operation ofthe vehicle system to decelerate the host vehicle according to theinitial acceleration control rate; and controlling the braking operationof the vehicle system to gradually decelerate the host vehicle from theinitial acceleration control rate to the modified acceleration controlrate.
 2. The computer-implemented method of claim 1, includingdetermining whether the second vehicle is a tailgating vehicle based oncomparing a time headway distance between the host vehicle and thesecond vehicle to a tailgating headway distance threshold.
 3. Thecomputer-implemented method of claim 2, including upon determining thesecond vehicle is the tailgating vehicle for a predetermined period oftime, increasing the preceding headway reference distance between thehost vehicle and the first vehicle.
 4. The computer-implemented methodof claim 2, including upon determining the second vehicle is thetailgating vehicle and upon detecting a second vehicle braking operationat the second vehicle using the one or more vehicle sensors, graduallyincreasing the preceding headway reference distance between the hostvehicle and the first vehicle.
 5. The computer-implemented method ofclaim 1, wherein upon determining the acceleration control rate does notmeet the braking rate threshold, controlling the braking operation ofthe vehicle system includes gradually decelerating the host vehicleaccording to the acceleration control rate, the first vehicle, and thesecond vehicle.
 6. A vehicle system for a host vehicle that controlsmotion of the host vehicle relative to a first vehicle positionedimmediately ahead of the host vehicle, comprising: a sensor systemincluding one or more vehicle sensors; and a processor operativelyconnected for computer communication with the sensor system, wherein theprocessor: detects, using the one or more vehicle sensors, a secondvehicle driving behind the host vehicle and in the same lane as the hostvehicle; receives from the vehicle system of the host vehicle anacceleration control rate that when executed by the host vehicleinitiates a braking operation by the vehicle system of the host vehicleto maintain a preceding headway reference distance with the firstvehicle; determines, using the one or more vehicle sensors, a relativerear headway distance between the host vehicle and the second vehiclewith respect to a rear headway reference distance; determines, using theone or more vehicle sensors, whether the second vehicle is within atailgating headway distance threshold from the host vehicle for apredetermined period of time; determines a modified acceleration controlrate based on the relative rear headway distance and the rear headwayreference distance, and an initial acceleration control rate based onthe relative rear headway distance and the rear headway referencedistance, wherein the initial acceleration control rate is less than themodified acceleration control rate; controls the braking operation ofthe vehicle system to decelerate the host vehicle according to theinitial acceleration control rate; and upon detecting a second vehiclebraking operation at the second vehicle using the one or more vehiclesensors, controls the braking operation of the vehicle system togradually decelerate the host vehicle from the initial accelerationcontrol rate to the modified acceleration control rate.
 7. The vehiclesystem of claim 6, wherein the processor modifies the accelerationcontrol rate and controls the braking operation thereby increasing thepreceding headway reference distance between the host vehicle and thefirst vehicle.
 8. The vehicle system of claim 6, wherein the processordetermines the acceleration control rate meets a braking rate threshold,and the processor controls the braking operation of the vehicle systemby decelerating the host vehicle according to the acceleration controlrate and the first vehicle.
 9. The vehicle system of claim 6, whereinthe processor determines the acceleration control rate does not meet abraking rate threshold, and the processor controls the braking operationof the vehicle system by gradually decelerating the host vehicleaccording to the acceleration control rate, the first vehicle, and thesecond vehicle.
 10. A non-transitory computer-readable storage mediumincluding instructions that when executed by a processor, cause theprocessor to: detect a second vehicle driving behind a host vehicle andin the same lane as the host vehicle; receive an acceleration controlrate from a vehicle system of a host vehicle, wherein the accelerationcontrol rate is generated by the vehicle system to maintain a precedingheadway reference distance with a first vehicle positioned immediatelyahead of the host vehicle; determine a braking operation initiated bythe host vehicle based on the acceleration control rate by comparing theacceleration control rate to a braking rate threshold; calculate arelative rear headway distance between the host vehicle and the secondvehicle with respect to a rear headway reference distance; calculates amodified acceleration control rate based on the relative rear headwaydistance and the rear headway reference distance, and an initialacceleration control rate based on the relative rear headway distanceand the rear headway reference distance, wherein the initialacceleration control rate is less than the modified acceleration controlrate; generates one or more braking signals to gradually increasedeceleration of the host vehicle from the initial acceleration controlrate to the modified acceleration control; and transmits the one or morebraking systems to the vehicle system.
 11. The non-transitorycomputer-readable storage medium of claim 10, wherein the processordetermines whether the second vehicle is a tailgating vehicle based oncomparing a time headway distance between the host vehicle and thesecond vehicle to a tailgating headway distance threshold.